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  • 1.
    Campillo, Javier
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Barberis, Stefano
    University of Genoa, Italy.
    Traverso, Alberto
    University of Genoa, Italy.
    Kyprianidis, Konstantinos
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Vassileva, Iana
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Open-Source Modelling and Simulation of Microgrids and Active Distribution Networks2015In: Sustainable Places 2015, Conference Proceedings, Sigma Orionis , 2015, p. 91-99Conference paper (Refereed)
    Abstract [en]

    Distributed generation, and active distribution networks constitute an economic and technically viable alternative for reducing green house gases emissions and increase the use of renewable energy sources in local distribution grids. These active networks allow replacing large generators, usually located far from the consumption loads, thus considerably minimizing distribution losses and increase renewable energy penetration. However, designing and successfully controlling these complex networks, becomes a great engineering challenge; most computational modeling and simulation tools available for these systems are either focused on the individual generation components themselves, or the economic dispatch of multiple generators. Moreover, these tools often rely on closed source commercial software that use manufacturers' data for predefining the parameters of the models' components. This approach does not provide enough flexibility to users, since often is not possible to adjust these parameters. This paper presents object- oriented, component-based, open software components for simulating and optimizing the operation of active distribution networks, including multiple distributed generators and energy using the Modelica open-source modeling language. 

  • 2.
    Celis, Cesar
    et al.
    Cranfield University, UK.
    Mohseni, Martina
    Cranfield University, UK.
    Kyprianidis, Konstantinos G.
    Mälardalen University, School of Business, Society and Engineering. Cranfield University, UK.
    Sethi, Vishal
    Cranfield University, UK.
    Ogaji, Stephen O. T.
    Cranfield University, UK.
    Haslam, Antony
    Cranfield University, UK.
    Pilidis, Pericles
    Cranfield University, UK.
    Multidisciplinary Design Optimization of Aero Engines: Environmental Performance-Based Methodology2008In: SYMKOM’08 Proceedings. CIEPLNE MASZYNY PRZEPLYWOWE. TURBOMACHINERY. No.133, 2008Conference paper (Refereed)
    Abstract [en]

    A methodology and tool that allows evaluating and quantifying aero engines design trade-offs originated as a consequence of addressing conflicting objectives such as low environmental impact and low operating costs is presented, and applied to a general case study to assess the feasibility of using new highly efficient engine configurations: intercooled- recuperated (ICR) engines. The case study results show that according to the ICR systems performance (heat exchangers effectiveness, pressure losses, and weight penalty) they could find usage in practical applications.

  • 3.
    Colmenares, Fernando
    et al.
    Cranfield University, Cranfield, Bedfordshire, England, UK.
    Kyprianidis, Konstantinos
    Cranfield University, Cranfield, Bedfordshire, England, UK.
    Gómez, Josué
    Cranfield University, Cranfield, Bedfordshire, England, UK.
    Ogaji, Stephen
    Cranfield University, Cranfield, Bedfordshire, England, UK.
    Pilidis, Pericles
    Cranfield University, Cranfield, Bedfordshire, England, UK.
    Latorre, Sergio
    Universidad de Antioquia, Medellín, Colombia.
    Future Aero-Engines’ Optimisation for Minimal Fuel Burn2008In: ASME Turbo Expo 2008: Power for Land, Sea, and AirVolume 2: Controls, Diagnostics and Instrumentation; Cycle Innovations; Electric PowerBerlin, Germany, June 9–13, 2008, 2008, p. 411-416Conference paper (Refereed)
    Abstract [en]

    While aircraft environmental performance has been important since the beginnings of commercial aviation, continuously increasing passenger traffic and a rise in public awareness have made aircraft noise and emissions two of the most pressing issues hampering commercial aviation growth today. The air transportation for the new millennium will require revolutionary solutions to meeting public demand for improving safety, reliability, environmental compatibility, and affordability. The objective of this research is to assess the trade-off between operating costs and environmental requirements of the future aero engines for short range commercial aircrafts. This involves optimising the engines’ design point to minimise the block fuel and evaluating the economic and environmental impact. A high by-pass ratio turbofan engine with performance characteristics and technology from the year 2000 was set up as a baseline and compared to very high by-pass ratio turbofans. The results present a great potential benefit of the geared turbofan compared to high BPR one (baseline) to reduce cruise CO2 emissions and noise; however this may involve NOx penalties, that is an increase of 5.1% in comparison to the baseline. The CRTF engine seems to be, at least according to the simulations, a very promising solution in terms of environmental and economical performance. This is one on the series of work that would be carried out on the cycles being assessed in this paper (feasibility study). Further work on the specific technical issues — such as: technological implications — would be published when completed.

  • 4.
    Cunha, Henrique E.
    et al.
    Chalmers University of Technology.
    Kyprianidis, Konstantinos G.
    Chalmers University of Technology.
    Investigation of the Potential of Gas Turbines for Vehicular Applications2012In: Proc. ASME. 44694; Volume 3: Cycle Innovations; Education; Electric Power; Fans and Blowers; Industrial and Cogeneration. GT2012-68402, 2012, p. 51-64Conference paper (Refereed)
    Abstract [en]

    Nowadays, the reduction of fuel consumption and pollutant emissions has become a top priority for society and economy. In the past decades, some of the environmental advantages of the gas turbine (such as inherently low CO and unburned HC) have led some car manufacturers to evaluate the potential of this type of engine as prime mover. This paper suggests a strategy to assess the fuel consumption of gas turbines applied in road vehicles. Based on a quasistatic approach, a model was created that can simulate road vehicles powered by gas turbines, and thereafter a comparison was established with reciprocating engines. Within this study, material and turbomachinery technology developments that have taken place in micro gas turbines since the 1960’s have been considered. A 30% efficiency improvement target has been identified with respect to making the gas turbine fuel competitive to a diesel engine powering an SUV. It is the authors’ view that several technologies that could mature sufficiently within the next 10–15 years exist, such as uncooled ceramic turbines. Such technologies could help bridge the fuel efficiency gap in micro gas turbines and make them commercially competitive in the future for low-emissions vehicular applications. Furthermore, the system developed also allows the simulation of hybrid configurations using gas turbines as range extenders, a solution that some car manufacturers consider to be the most promising in the coming years.

  • 5.
    Da Silva, Edna
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Kyprianidis, Konstantinos
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Säterskog, M.
    Saab AB, Linköping, Sweden.
    Camacho, R. G. R.
    Federal University of Itajubá, Itajubá, MG, Brazil.
    Sarmiento, A. L. E.
    FederalCenter of Technology Education, Rio de Janeiro, RJ, Brazil.
    Preliminary design optimization of an organic Rankine cycle radial turbine rotor2017In: PROCEEDINGS OF THE ASME TURBO EXPO: TURBINE TECHNICAL CONFERENCE AND EXPOSITION, 2017, VOL 3, American Society of Mechanical Engineers (ASME) , 2017, Vol. 3, article id V003T06A018Conference paper (Refereed)
    Abstract [en]

    The present study describes the application of a preliminary design approach for the optimization of an organic Rankine cycle radial turbine. Losses in the nozzle the rotor have initially been modelled using a mean-line design approach. The work focuses on a typical small-scale application of 50 kW, and two working fluids, R245fa (1,1,1,3,3,-pentafluoropropane) and R236fa (1,1,1,3,3,3-hexafluoropropane) are considered for validation purposes. Real gas formulations have been used based on the NIST REFPROP database. The validation is based on a design from the literature, and the results demonstrate close agreement the reference geometry and thermodynamic parameters. The total-to-total efficiencies of the reference turbine designs were 72% and 79%. Following the validation exercise, an optimization process was performed using a controlled random search algorithm with the turbine efficiency set as the figure of merit. The optimization focuses on the R245fa working fluid since it is more suitable for the operating conditions of the proposed cycle, enables an overpressure in the condenser and allows higher system efficiency levels. The R236fa working fluid was also used for comparison with the literature, and the reason is the positive slope of the saturation curve, somehow is possible to work with lower temperatures. Key preliminary design variables such as flow coefficient, loading coefficient, and length parameter have been considered. While several optimized preliminary designs are available in the literature with efficiency levels of up to 90%, the preliminary design choices made will only hold true for machines operating with ideal gases, i.e. typical exhaust gases from an airbreathing combustion engine. For machines operating with real gases, such as organic working fluids, the design choices need to be rethought and a preliminary design optimization process needs to be introduced. The efficiency achieved in the final radial turbine design operating with R245fa following the optimization process was 82.4%. A three-dimensional analysis of the flow through the blade section using computational fluid dynamics was carried out on the final optimized design to confirm the preliminary design and further analyze its characteristics.

  • 6.
    Dahlquist, Erik
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Naqvi, Muhammad
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Thorin, Eva
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Yan, Jinyue
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Kyprianidis, Konstantinos
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Comparison of Gas Quality from Black Liquor and Wood Pellet Gasification Using Modelica Simulation and Pilot Plant Results2017In: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 105, p. 992-998Article in journal (Refereed)
    Abstract [en]

    There is a potential to integrate biomass gasification with pulp & paper and CHP plants in order to complement the existing systems with production of chemicals, such as methane, hydrogen, and methanol etc. To perform system analysis of such integration, it is important to gain knowledge of relevant input data on expected synthesis gas composition by gasifying different types of feed stock. In this paper, the synthesis gas quality from wood pellets gasification (WPG) has been compared with black liquor gasification (BLG) through modeling and experimental results at pilot scale. In addition, the study develops regression models like Partial Least Squares (PLS) made from the experimental data. The regression models are then combined with dynamic models developed in Modelica for the investigation of dynamic energy and material balances for integrated plants. The data presented in this study could be used as input to relevant analysis using e.g. ASPEN plus and similar system analysis tools. 

  • 7.
    Dahlquist, Erik
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Naqvi, Muhammad
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Thorin, Eva
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Yan, Jinyue
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center. Royal Institute of Technology (KTH), Sweden.
    Kyprianidis, Konstantinos
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Hartwell, Philip
    BioRegional MiniMills Ltd, UK.
    Experimental and numerical investigation of pellet and black liquor gasification for polygeneration plant2017In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 204, p. 1066-1064Article in journal (Refereed)
    Abstract [en]

    It is vital to perform system analysis on integrated biomass gasification in chemical recovery systems in pulp and paper and heat and power plants for polygeneration applications. The proposed integration complements existing pulp and paper and heat and power production systems with production of chemicals such as methane and hydrogen. The potential to introduce gasification-based combined cycles comprising gas turbines and steam turbines to utilize black liquors and wood pellets also merits investigation. To perform such analysis, it is important to first build knowledge on expected synthesis gas composition by gasifying at smaller scale different types of feed stock. In the present paper, the synthesis gas quality from wood pellets gasification has been compared with black liquor gasification by means of numerical simulation as well as through pilot-scale experimental investigations. The experimental results have been correlated into partial least squares models to predict the composition of the synthesis gas produced under different operating conditions. The gas quality prediction models are combined with physical models using a generic open-source modelling language for investigating the dynamic performance of large-scale integrated polygeneration plants. The analysis is further complemented by considering potential gas separation using modern membrane technology for upgrading the synthesis gas with respect to hydrogen content. The experimental data and statistical models presented in this study form an important literature source for future use by the gasification and polygeneration research community on further integrated system analysis.

  • 8.
    Dahlquist, Erik
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Naqvi, Muhammad
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center. KTH, Energiprocesser.
    Thorin, Eva
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Yan, Jinyue
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center. KTH, Energiprocesser.
    Kyprianidis, Konstantinos
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Hartwell, Philip
    BioRegional MiniMills Ltd., United Kingdom.
    Modeling of Black Liquor Gasification2016Conference paper (Refereed)
  • 9.
    Dahlquist, Erik
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Naqvi, Muhammad
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center. KTH, Energiprocesser.
    Thorin, Eva
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Yan, Jinyue
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center. KTH, Energiprocesser.
    Kyprianidis, Konstantinos
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Hartwell, Philip
    BioRegional MiniMills Ltd., United Kingdom.
    Modeling of Wood Gasification in an Atmospheric CFB Plant2016Conference paper (Refereed)
  • 10.
    Efstathiadis, T.
    et al.
    Aristotle Univ Thessaloniki, Greece.
    Kalfas, A. I.
    Aristotle Univ Thessaloniki, Greece.
    Seferlis, P.
    Aristotle Univ Thessaloniki, Greece.
    Kyprianidis, Konstantinos
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Rivarolo, M.
    Univ Genoa, Italy.
    Geometry Optimization of Power Production Turbine For A Low Enthalpy (<= 100 degrees C) ORC System2015In: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 75, p. 1624-1630Article in journal (Refereed)
    Abstract [en]

    The present paper is examining the geometry optimization of a power production turbine, in the range of 100kW(el), for a low enthalpy Organic Rankine cycle system (<= 100 degrees C). In the last years, accelerated consumption of fossil fuels has caused many serious environmental problems such as global warming, ozone layer destruction and atmospheric pollution. It is this reason that a growing trend towards exploiting low-enthalpy content energy sources has commenced and led to a renewed interest in small-scale turbines for Organic Rankine Cycle applications. The design concept for such turbines can be quite different from either standard gas or steam turbine designs. The limited enthalpic content of many energy sources imposes the use of organic working media, with unusual properties for the turbine. A versatile cycle design and optimization requires the parameterization of the main turbine design. There are many potential applications of this power-generating turbine, including geothermal and concentrate solar thermal fields or waste heat of steam turbine exhausts. An integrated model of equations has been developed, thus creating a model to assess the performance of an organic cycle for various working fluids such as R134a and isobutane-isopentane mixture. The most appropriate working fluid has been chosen, taking its influence on both cycle efficiency and the specific volume ratio into consideration. This choice is of particular importance at turbine extreme operating conditions, which are strongly related to the turbine size. In order to assess the influence of various design parameters, a turbine design tool has been developed and applied to define the geometry of blades in a preliminary stage. Finally, as far as the working fluid is concerned, the mixture of 85% isopentane-15% isobutane has been chosen as the most suitable fluid for the low enthalpy ORC system, since its output net power is 10% higher compared to the output net power of R134a. 

  • 11.
    Goldberg, C.
    et al.
    Cranfield University, Bedfordshire, United Kingdom.
    Nalianda, D.
    Cranfield University, Bedfordshire, United Kingdom.
    Sethi, V.
    Cranfield University, Bedfordshire, United Kingdom.
    Pilidis, P.
    Cranfield University, Bedfordshire, United Kingdom.
    Singh, R.
    Cranfield University, Bedfordshire, United Kingdom.
    Kyprianidis, Konstantinos
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Assessment of an energy-efficient aircraft concept from a techno-economic perspective2018In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 221, p. 229-238Article in journal (Refereed)
    Abstract [en]

    An increase in environmental awareness in both the aviation industry and the wider global setting has led to large bodies of research dedicated to developing more sustainable technology with a lower environmental impact and lower energy usage. The goal of reducing environmental impact has necessitated research into revolutionary new technologies that have the potential to be significantly more energy efficient than their predecessors. However, for innovative technologies in any industry, there is a risk that adoption will be prohibitively expensive for commercial application. It is therefore important to model the economic factors of the new technology or policy at an early stage of development. This research demonstrates the application of a Techno-economic Environmental Risk Assessment framework that may be used to identify the economic impact of an energy-efficient aircraft concept and the impact that environmental policy would have on the viability of the concept. The framework has been applied to a case study aircraft designed to achieve an energy saving of 60% in comparison to a baseline 2005 entry-into-service aircraft. The model compares the green aircraft concept to a baseline conventional aircraft using a sensitivity analysis of the aircraft direct operating cost to changes in acquisition and maintenance cost. The research illustrates an economically viable region for the technology. Cost margins are identified where the increase in operating cost due to expensive novel technology is counterbalanced by the reduction in cost resulting from low energy consumption. Viability was found to be closely linked to fuel price, with a low fuel price limiting the viability of energy-efficient aviation technology. In contrast, a change in environmental taxation policy was found to be beneficial, with the introduction of carbon taxation incentivising the use of an environmentally optimised aircraft.

  • 12.
    Hermansson, K.
    et al.
    Sigholm Konsult, Västerås, Sweden.
    Kos, C.
    Flowocean AB, Västerås, Sweden.
    Starfelt, F.
    Vattenfall AB, Uppsala, Sweden.
    Kyprianidis, Konstantinos
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Lindberg, Carl-Fredrik
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center. ABB Corporate Research, Västerås, Sweden.
    Zimmerman, Nathan
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    An Automated Approach to Building and Simulating Dynamic District Heating Networks2018In: IFAC-PapersOnLine, ISSN 2405-8963, Vol. 51, no 2, p. 855-860Article in journal (Refereed)
    Abstract [en]

    In Nordic countries, district heating accounts for a large share of the consumers’  heat demand. In Sweden, roughly 50% of the total heat demand is attributed to district heating. Which, over the past few years, is equivalent to around 50 TWh, and imposes a difficult balance between supply and demand for the suppliers of district heating. For large networks the propagation of heat from supplier to end-user can vary several hours. Further complexities of large networks, which can consist of multiple overlapping rings, is that during transient conditions the flow can actually change direction. A dynamic modeling library has been developed in Modelica using OpenModelica for district heating networks. Methods for modeling, handling data, simulating and the visualization of results has been developed using Matlab. The model has been validated using data from Mälarenergi  AB, a local provider of district heating in Västerås, Sweden. The model provides to an acceptable degree in predicting the heat propagation and temperature distribution in a localized case study. Adding a higher level of robustness, the model has the capacity to handle bi-directional and reversing flows in complex ring structures. Through this work, the combination of OpenModelica and Matlab, a framework for automating the building and simulation of district heating networks is obtainable. The implications of automating network modeling from computer-aided design drawings allows for a quick robust overview of how the network is working and how prospective additions to the network could impact the end-users. Furthermore, incorporating visual aspects for heat propagation in a network contributes to a higher understanding of complex network structures. 

  • 13.
    Kyprianidis, Konstantinos
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center. Cranfield University.
    Camilleri, William
    Cranfield University, Cranfield, UK.
    Gas Turbines for Power and Propulsion2015In: Handbook of Clean Energy Systems: Volume 2 - Clean Energy Conversion Technologies / [ed] Jinyue Yan, Chichester, West Sussex, UK: John Wiley & Sons, 2015, 1, p. 1-25Chapter in book (Refereed)
    Abstract [en]

    For over seven decades, the gas turbine has been used successfully in a variety of applications including aircraft, ship, and surface vehicle propulsion as well as for electrical power and heat generation. The gas turbine is in essence a type of internal combustion engine comprising in its simplest form a compressor, a combustor, and a turbine. It can utilize a variety of different fuels, most commonly natural gas and kerosene (Jet-A).

    The gas turbine has played a key role in the expansion of jet transportation and is currently the prime mover for almost all commercial applications, other than light aircraft. It also has had a considerable impact in the power generation sector with efficiencies in excess of 40% for simple cycles, and close to 60% for combined cycles. Over the next decades, it is expected that the gas turbine will continue to play a significant role in the power generation and propulsion market.

    This article covers the fundamentals of gas turbine design, performance, and future technology development. First, a short presentation of the fundamental thermodynamics relating to the gas turbine is given. It is followed by an ideal analysis of three major cycles: the simple cycle, the intercooled cycle, and the intercooled recuperated cycle. Typical losses for gas turbine components are discussed along with relevant performance modeling methods. The fundamental principles of gas turbine conceptual design are presented followed by an assessment of the real performance of the three major cycles. Finally, a critical review is presented of future gas turbine concepts and their enabling technologies, with the primary focus on civil aircraft propulsion. Recent development trends and the primary research and development efforts by major gas turbine manufacturers are discussed in detail.

  • 14.
    Kyprianidis, Konstantinos
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Dahlquist, Erik
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    On the trade-off between aviation NOx and energy efficiency2017In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 185, p. 1506-1516Article in journal (Refereed)
    Abstract [en]

    This study aims to assess the trade-off between the ever-increasing energy efficiency of modern aero-engines and their   performance. The work builds on performance models previously developed to optimise the specific fuel consumption of future aero-engine designs. As part of the present work a simple and adaptable   emissions correlation for Rich-burn Quick-quench Lean-burn combustor designs is derived. The proposed model is computationally inexpensive and sufficiently accurate for use in aero-engine multi-disciplinary conceptual design tools. Furthermore, it is possible to adapt the correlation to model the   emissions of combustors designed for very aggressive future cycles. An approach to lean-burn combustor   emissions modelling is also presented. The simulation results show that improving engine propulsive efficiency is likely to have a benign effect on  emissions at high altitude; at sea-level conditions   emissions are particularly likely to reduce. Improving engine thermal efficiency however has a detrimental effect on   emissions from RQL combustors, both at high altitude and particularly at sea-level conditions. LDI combustor technology does not demonstrate such behaviour. Current legislation permits trading   emissions engine efficiency and hence reduce   emissions. If we are to reduce the contribution of aviation to global warming, however, future certification legislation may need to become more stringent and comprehensive.

  • 15.
    Kyprianidis, Konstantinos G.
    Mälardalen University, School of Business, Society and Engineering. Cranfield University.
    Dynamic Simulation of Aircraft Propulsion Systems2006Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • 16.
    Kyprianidis, Konstantinos G.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center. Cranfield University.
    Future Aero Engine Designs: An Evolving Vision2011In: Advances in Gas Turbine Technology / [ed] Ernesto Benini, Rijeka, Croatia: InTech, 2011, 1st, p. 3-24Chapter in book (Other academic)
  • 17.
    Kyprianidis, Konstantinos G.
    Cranfield University, UK.
    Multi-Disciplinary Conceptual Design of Future Jet Engine Systems2010Doctoral thesis, monograph (Other academic)
    Abstract [en]

    This thesis describes various aspects of the development of a multi-disciplinary aero engine conceptual design tool, TERA2020 (Techno-economic, Environmental and Risk Assessment for 2020), based on an explicit algorithm that considers: engine performance, engine aerodynamic and mechanical design, aircraft design and performance, emissions prediction and environmental impact, engine and airframe noise, and production, maintenance and direct operating costs.

    As part of this research effort, a newly-derived semi-empirical NOx correlation for modern rich-burn single-annular combustors is proposed. The development of a numerical methods library is also presented, including an improved gradient-based algorithm for solving non-linear equation systems. Common assumptions made in thermo-fluid modelling for gas turbines and their effect on caloric properties are investigated, while the impact of uncertainties on performance calculations and emissions predictions at aircraft system level is assessed. Furthermore, accuracy limitations in assessing novel engine core concepts as imposed by current practice in thermo-fluid modelling are identified.

    The TERA2020 tool is used for quantifying the potential benefits from novel technologies for three low pressure spool turbofan architectures.  The impact of failing to deliver specific component technologies is quantified, in terms of power plant noise and CO2 emissions. To address the need for higher engine thermal efficiency, TERA2020 is again utilised; benefits from the potential introduction of heat-exchanged cores in future aero engine designs are explored and a discussion on the main drivers that could support such initiatives is presented. Finally, an intercooled core and conventional core turbofan engine optimisation procedure using TERA2020 is presented. A back-to-back comparison between the two engine configurations is performed and fuel optimal designs for 2020 are proposed.

    Whilst the detailed publications and the work carried out by the author, in a collaborative effort with other project partners, is presented in the main body of this thesis, it is important to note that this work is supported by 20 conference and journal papers.

  • 18.
    Kyprianidis, Konstantinos G.
    et al.
    Cranfield University, Bedfordshire, England, UK.
    Colmenares Quintero, Ramon F.
    Cranfield University, Bedfordshire, England, UK.
    Pascovici, Daniele S.
    Cranfield University, Bedfordshire, England, UK.
    Ogaji, Stephen O. T.
    Cranfield University, Bedfordshire, England, UK.
    Pilidis, Pericles
    Cranfield University, Bedfordshire, England, UK.
    Kalfas, Anestis I.
    Aristotle University of Thessaloniki, Thessaloniki, Greece.
    EVA: A Tool for EnVironmental Assessment of Novel Propulsion Cycles2008In: ASME Turbo Expo 2008: Power for Land, Sea, and AirVolume 2: Controls, Diagnostics and Instrumentation; Cycle Innovations; Electric PowerBerlin, Germany, June 9–13, 2008, 2008, p. 547-556Conference paper (Refereed)
    Abstract [en]

    This paper presents the development of a tool for EnVironmental Assessment (EVA) of novel propulsion cycles implementing the Technoeconomical Environmental and Risk Analysis (TERA) approach. For nearly 3 decades emissions certification and legislation has been mainly focused on the landing and take-off cycle. Exhaust emissions measurements of NOx, CO and unburned hydrocarbons are taken at Sea Level Static (SLS) conditions for 4 different power settings (idle, descent, approach and take-off) and are consecutively used for calculating the total emissions during the ICAO landing and take-off cycle. With the global warming issue becoming ever more important, stringent emissions legislation is soon to follow, focusing on all flight phases of an aircraft. Unfortunately, emissions measurements at altitude are either extremely expensive, as in the case of altitude test facility measurements, or unrealistic, as in the case of direct in flight measurements. Compensating for these difficulties, various existing methods can be used to estimate emissions at altitude from ground measurements. Such methods, however, are of limited help when it comes to assessing novel propulsion cycles or existing engine configurations with no SLS measurements available. The authors are proposing a simple and fast method for the calculation of SLS emissions, mainly implementing ICAO exhaust emissions data, corrections for combustor inlet conditions and technology factors. With the SLS emissions estimated, existing methods may be implemented to calculate emissions at altitude. The tool developed couples emissions predictions and environmental models together with engine and aircraft performance models in order to estimate the total emissions and Global Warming Potential of novel engine designs during all flight phases (i.e. the whole flight cycle). The engine performance module stands in the center of all information exchange. In this study, EVA and the described emissions prediction methodology have been used for the preliminary design analysis of three spool high bypass ratio turbofan engines. The capability of EVA to radically explore the design space available in novel engine configurations, while accounting for fuel burn and global warming potential during the whole flight cycle of an aircraft, is illustrated.

  • 19.
    Kyprianidis, Konstantinos G.
    et al.
    Chalmers University of Technology, Sweden.
    Grönstedt, Tomas
    Chalmers University of Technology, Sweden.
    Barbosa, Joao R.
    Instituto Tecnológico de Aeronáutica - ITA, Sao Paolo, Brazil.
    Lessons Learned from the Development of Courses on Gas Turbine Multi-disciplinary Conceptual Design2012In: Proc. ASME. 44694; Volume 3: Cycle Innovations; Education; Electric Power; Fans and Blowers; Industrial and Cogeneration. GT2012-70095, 2012, p. 513-523Conference paper (Refereed)
    Abstract [en]

    Despite the need for highly qualified experts, multi-disciplinary gas turbine conceptual design has not been a common study topic in traditional post-graduate curriculums. Although many courses on specialised topics in gas turbine technology take place, limited attention is given on connecting these individual topics to the overall engine design process. Teaching conceptual design as part of a post-graduate curriculum, or as an intensive short course, may help to address the industrial need for engineers with early qualifications on the topic i.e., prior to starting their careers in the gas turbine industry.

    This paper presents details and lessons learned from: (i) the integration of different elements of conceptual design in an existing traditional MSc course on gas turbine technology through the introduction of group design tasks, and (ii) the development of an intensive course on gas turbine multi-disciplinary conceptual design as a result of an international cooperation between academia and industry.

    Within the latter course, the students were grouped in competing teams and were asked to produce their own gas turbine conceptual design proposals within a given set of functional requirements. The main concept behind the development of the new design tasks, and the new intensive course, has been to effectively mimic the dynamics of small conceptual design teams, as often encountered in industry. The results presented are very encouraging, in terms of enhancing student learning and developing engineering skills.

  • 20.
    Kyprianidis, Konstantinos G.
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center. Cranfield University.
    Sethi, Vishal
    Cranfield University.
    Ogaji, Stephen O. T.
    Cranfield University.
    Pilidis, Pericles
    Cranfield University.
    Singh, Riti
    Cranfield University.
    Kalfas, Anestis I.
    Aristotle University of Thessaloniki.
    Thermo-Fluid Modelling for Gas Turbines-Part I: Theoretical Foundation and Uncertainty Analysis2009In: ASME TURBO EXPO 2009 Proceedings, GT2009-60092, 2009Conference paper (Refereed)
    Abstract [en]

    In this two-part publication, various aspects of thermo-fluidmodelling for gas turbines are described and their impact onperformance calculations and emissions predictions at aircraftsystem level is assessed. Accurate and reliable fluid modellingis essential for any gas turbine performance simulation softwareas it provides a robust foundation for building advanced multidisciplinarymodelling capabilities. Caloric properties forgeneric and semi-generic gas turbine performance simulationcodes can be calculated at various levels of fidelity; selection ofthe fidelity level is dependent upon the objectives of thesimulation and execution time constraints. However, rigorousfluid modelling may not necessarily improve performancesimulation accuracy unless all modelling assumptions andsources of uncertainty are aligned to the same level. Certainmodelling aspects such as the introduction of chemical kinetics,and dissociation effects, may reduce computational speed andthis is of significant importance for radical space explorationand novel propulsion cycle assessment.

    This paper describes and compares fluid models, based ondifferent levels of fidelity, which have been developed for anindustry standard gas turbine performance simulation code and an environmental assessment tool for novel propulsion cycles.The latter comprises the following modules: engineperformance, aircraft performance, emissions prediction, andenvironmental impact. The work presented aims to fill thecurrent literature gap by: (i) investigating the commonassumptions made in thermo-fluid modelling for gas turbinesand their effect on caloric properties and (ii) assessing theimpact of uncertainties on performance calculations andemissions predictions at aircraft system level.

    In Part I of this two-part publication, a comprehensiveanalysis of thermo-fluid modelling for gas turbines is presentedand the fluid models developed are discussed in detail.Common technical models, used for calculating caloricproperties, are compared while typical assumptions made influid modelling, and the uncertainties induced, are examined.Several analyses, which demonstrate the effects of composition,temperature and pressure on caloric properties of workingmediums for gas turbines, are presented. The working mediumsexamined include dry air and combustion products for variousfuels and H/C ratios. The errors induced by ignoringdissociation effects are also discussed.

  • 21.
    Kyprianidis, Konstantinos G.
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center. Cranfield University.
    Sethi, Vishal
    Cranfield University.
    Ogaji, Stephen O. T.
    Cranfield University.
    Pilidis, Pericles
    Cranfield University.
    Singh, Riti
    Cranfield University.
    Kalfas, Anestis I.
    Aristotle University of Thessaloniki.
    Thermo-Fluid Modelling for Gas Turbines-Part II: Impact on Performance Calculations and Emissions Predictions at Aircraft System Level2009In: ASME TURBO EXPO 2009 Proceedings, GT-2009-60101, 2009, p. 483-494Conference paper (Refereed)
    Abstract [en]

    In this two-part publication, various aspects of thermo-fluidmodelling for gas turbines are described and their impact onperformance calculations and emissions predictions at aircraftsystem level is assessed. Accurate and reliable fluid modellingis essential for any gas turbine performance simulation softwareas it provides a robust foundation for building advanced multidisciplinarymodelling capabilities. Caloric properties forgeneric and semi-generic gas turbine performance simulationcodes can be calculated at various levels of fidelity; selection ofthe fidelity level is dependent upon the objectives of thesimulation and execution time constraints. However, rigorousfluid modelling may not necessarily improve performancesimulation accuracy unless all modelling assumptions andsources of uncertainty are aligned to the same level. Certainmodelling aspects such as the introduction of chemical kinetics,and dissociation effects, may reduce computational speed andthis is of significant importance for radical space explorationand novel propulsion cycle assessment.

    This paper describes and compares fluid models, based ondifferent levels of fidelity, which have been developed for anindustry standard gas turbine performance simulation code and an environmental assessment tool for novel propulsion cycles.The latter comprises the following modules: engineperformance, aircraft performance, emissions prediction, andenvironmental impact. The work presented aims to fill thecurrent literature gap by: (i) investigating the commonassumptions made in thermo-fluid modelling for gas turbinesand their effect on caloric properties and (ii) assessing theimpact of uncertainties on performance calculations andemissions predictions at aircraft system level.

    In Part II of this two-part publication, the uncertaintyinduced in performance calculations by common technicalmodels, used for calculating caloric properties, is discussed atengine level. The errors induced by ignoring dissociation areexamined at 3 different levels: i) component level, ii) enginelevel, and iii) aircraft system level. Essentially, an attempt ismade to shed light on the trade-off between improving theaccuracy of a fluid model and the accuracy of a multidisciplinarysimulation at aircraft system level, againstcomputational time penalties. The results obtained demonstratethat accurate modelling of the working fluid is not alwaysessential; the accuracy/uncertainty for an overall engine modelwill always be better than the mean accuracy/uncertainty of the individual component estimates as long as systematic errors arecarefully examined and reduced to acceptable levels to ensureerror propagation does not cause significant discrepancies.Computational time penalties induced by improving theaccuracy of the fluid model as well as the validity of the idealgas assumption for future turbofan engines and novelpropulsion cycles are discussed.

  • 22.
    Kyprianidis, Konstantinos
    et al.
    Mälardalen University, School of Business, Society and Engineering. Mälardalen University, School of Business, Society and Engineering, Future Energy Center. Cranfield University, UK.
    Grönstedt, Tomas
    Chalmers University of Technology, Sweden.
    Barbosa, Joao R.
    Instituto Technológico de Aeronáutica, São José dos Campos, Brazil.
    Lessons Learned From the Development of Courses on Gas Turbine Multidisciplinary Conceptual Design2013In: Journal of engineering for gas turbines and power, ISSN 0742-4795, E-ISSN 1528-8919, Vol. 135, no 7, p. Article number 072601-Article in journal (Refereed)
    Abstract [en]

    Despite the need for highly qualified experts, multidisciplinary gas turbine conceptual design has not been a common study topic in traditional postgraduate curriculums. Although many courses on specialized topics in gas turbine technology take place, limited attention is given on connecting these individual topics to the overall engine design process. Teaching conceptual design as part of a postgraduate curriculum, or as an intensive short course, may help to address the industrial need for engineers with early qualifications on the topic, i.e., prior to starting their careers in the gas turbine industry. This paper presents details and lessons learned from: (i) the integration of different elements of conceptual design in an existing traditional Master of Science (MSc) course on gas turbine technology through the introduction of group design tasks and (ii) the development of an intensive course on gas turbine multidisciplinary conceptual design as a result of an international cooperation between academia and industry. Within the latter course, the students were grouped in competing teams and were asked to produce their own gas turbine conceptual design proposals within a given set of functional requirements. The main concept behind the development of the new design tasks, and the new intensive course, has been to effectively mimic the dynamics of small conceptual design teams, as often encountered in industry. The results presented are very encouraging in terms of enhancing student learning and developing engineering skills.

  • 23.
    Kyprianidis, Konstantinos
    et al.
    Cranfield University, United Kingdom.
    Grönstedt, Tomas
    Chalmers University of Technology, Sweden.
    Ogaji, S. O. T.
    Cranfield University, United Kingdom.
    Pilidis, Pericles
    Cranfield University, United Kingdom.
    Singh, Riti
    Cranfield University, United Kingdom.
    Assessment of Future Aero-engine Designs With Intercooled and Intercooled Recuperated Cores2011In: Journal of Engineering for Gas Turbines and Power, ISSN 0742-4795, Vol. 133, no 1, article id 011701Article in journal (Refereed)
    Abstract [en]

    Reduction in CO2 emissions is strongly linked with the improvement of engine specific fuel consumption, as well as the reduction in engine nacelle drag and weight. Conventional turbofan designs, however, that reduce CO2 emissions—such as increased overall pressure ratio designs—can increase the production of NOx emissions. In the present work, funded by the European Framework 6 collaborative project NEW Aero engine Core concepts (NEWAC), an aero-engine multidisciplinary design tool, Techno-economic, Environmental, and Risk Assessment for 2020 (TERA2020), has been utilized to study the potential benefits from introducing heat-exchanged cores in future turbofan engine designs. The tool comprises of various modules covering a wide range of disciplines: engine performance, engine aerodynamic and mechanical design, aircraft design and performance, emissions prediction and environmental impact, engine and airframe noise, as well as production, maintenance and direct operating costs. Fundamental performance differences between heat-exchanged cores and a conventional core are discussed and quantified. Cycle limitations imposed by mechanical considerations, operational limitations and emissions legislation are also discussed. The research work presented in this paper concludes with a full assessment at aircraft system level that reveals the significant potential performance benefits for the intercooled and intercooled recuperated cycles. An intercooled core can be designed for a significantly higher overall pressure ratio and with reduced cooling air requirements, providing a higher thermal efficiency than could otherwise be practically achieved with a conventional core. Variable geometry can be implemented to optimize the use of the intercooler for a given flight mission. An intercooled recuperated core can provide high thermal efficiency at low overall pressure ratio values and also benefit significantly from the introduction of a variable geometry low pressure turbine. The necessity of introducing novel lean-burn combustion technology to reduce NOx emissions at cruise as well as for the landing and take-off cycle, is demonstrated for both heat-exchanged cores and conventional designs. Significant benefits in terms of NOx reduction are predicted from the introduction of a variable geometry low pressure turbine in an intercooled core with lean-burn combustion technology.

  • 24.
    Kyprianidis, Konstantinos
    et al.
    Aristotle University of Thessaloniki, Thessaloniki, Greece.
    Kalfas, Anestis I.
    Aristotle University of Thessaloniki, Thessaloniki, Greece.
    Dynamic performance investigations of a turbojet engine using a cross-application visual oriented platform2008In: Aeronautical Journal, ISSN 0001-9240, Vol. 112, no 1129, p. 161-169Article in journal (Refereed)
    Abstract [en]

    This paper presents the development of visual oriented tools for the dynamic performance simulation of a turbojet engine using a cross-application approach. In particular, the study focuses on the feasibility of developing simulation models using different programming environments and linking them together using a popular spreadsheet program. As a result of this effort, a low fidelity cycle program has been created, capable of being integrated with other performance models. The amount of laboratory sessions required for student training during an educational procedure, for example for a course in gas turbine performance simulation, is greatly reduced due to the familiarity of most students with the spreadsheet software. The model results have been validated using commercially available gas turbine simulation software and experimental data from open literature. The most important finding of this study is the capability of the program to link to aircraft performance models and predict the transient working line of the engine for various initial conditions in order to dynamically simulate flight phases including take-off and landing.

  • 25.
    Kyprianidis, Konstantinos
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center. Cranfield University, UK.
    Nalianda, Devaiah
    Cranfield University, UK.
    Dahlquist, Erik
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    A NOx Emissions Correlation for Modern RQL Combustors2015In: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 75, p. 2323-2330Article in journal (Refereed)
    Abstract [en]

    This study begins with a review of existing emissions prediction methodologies for Rich-burn Quick-quench Lean-burn combustors. The need for a simple and adaptable NOx emissions correlation for such combustor designs as used in state-of-the-art civil turbofan engines is discussed. The derivation of a new correlation is consequently presented. The proposed model is computationally inexpensive and sufficiently accurate for use in aero-engine multi-disciplinary conceptual design tools. Furthermore, it is possible to adapt the correlation to model the NOx emissions of combustors designed for very aggressive future cycles. A case study is presented focusing on the NOx performance of advanced future cycles relative to current and future certification limits.

  • 26.
    Kyprianidis, Konstantinos
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center. Cranfield University, UK.
    Rolt, Andrew
    Rolls-Royce plc, UK.
    On the Optimisation of a Geared Fan Intercooled Core Engine Design2014In: Journal of Engineering for Gas Turbines and Power, ISSN 0742-4795, Vol. 137, no 4, p. Paper No: GTP-14-1367-Article in journal (Refereed)
    Abstract [en]

    Reduction of CO2 emissions is strongly linked with the improvement of engine specific fuel consumption, as well as the reduction of engine nacelle drag and weight. One alternative design approach to improving specific fuel consumption is to consider a geared fan combined with an increased overall pressure ratio intercooled core performance cycle. Thermal benefits from intercooling have been well documented in the literature. Nevertheless, there is little information available in the public domain with respect to design space exploration of such an engine concept when combined with a geared fan. The present work uses a multidisciplinary conceptual design tool to further analyse the option of an intercooled core geared fan aero engine for long haul applications with a 2020 entry into service technology level assumption. The proposed design methodology is capable, with the utilised tool, of exploring the interaction of design criteria and providing critical design insight at engine-aircraft system level. Previous work by the authors focused on understanding the design space for this particular configuration with minimum specific fuel consumption, engine weight and mission fuel in mind. This was achieved by means of a parametric analysis, varying several engine design parameters - but only one at a time. The present work attempts to identify 'globally' fuel burn optimal values for a set of engine design parameters by varying them all simultaneously. This permits the non-linear interactions between the parameters to be accounted. Special attention has been given to the fuel burn impact of the reduced HPC efficiency levels associated with low last stage blade heights. Three fuel optimal designs are considered, based on different assumptions. The results indicate that it is preferable to trade overall pressure ratio and pressure ratio split exponent, rather than specific thrust, as means of increasing blade height and hence reducing the associated fuel consumption penalties. It is interesting to note that even when considering the effect of HPC last stage blade height on efficiency there is still an equivalently good design at a reduced overall pressure ratio. This provides evidence that the overall economic optimum could be for a lower overall pressure ratio cycle. Customer requirements such as take-off distance and time to height play a very important role in determining a fuel optimal engine design. Tougher customer requirements result in bigger and heavier engines that burn more fuel. Higher overall pressure ratio intercooled engine cycles clearly become more attractive in aircraft applications that require larger engine sizes.

  • 27.
    Kyprianidis, Konstantinos
    et al.
    Mälardalen University, School of Business, Society and Engineering. Mälardalen University, School of Business, Society and Engineering, Future Energy Center. Cranfield University, UK.
    Rolt, Andrew
    Rolls-Royce plc, UK.
    Grönstedt, Tomas
    Chalmers University of Technology, Sweden.
    Multidisciplinary Analysis of a Geared Fan Intercooled Core Aero-Engine2014In: Journal of engineering for gas turbines and power, ISSN 0742-4795, E-ISSN 1528-8919, Vol. 136, no 1, p. Article number 011203-Article in journal (Refereed)
    Abstract [en]

    The reduction of CO2 emissions is strongly linked with the improvement of engine specific fuel consumption, along with the reduction of engine nacelle drag and weight. One alternative design approach to improving specific fuel consumption is to consider a geared fan combined with an increased overall pressure ratio intercooled core performance cycle. The thermal benefits from intercooling have been well documented in the literature. Nevertheless, there is very little information available in the public domain with respect to design space exploration of such an engine concept when combined with a geared fan. The present work uses a multidisciplinary conceptual design tool to analyze the option of an intercooled core geared fan aero engine for long haul applications with a 2020 entry into service technology level assumption. With minimum mission fuel in mind, the results indicate as optimal values a pressure ratio split exponent of 0.38 and an intercooler mass flow ratio of 1.18 at hot-day top of climb conditions. At ISA midcruise conditions a specific thrust of 86 m/s, a jet velocity ratio of 0.83, an intercooler effectiveness of 56%, and an overall pressure ratio value of 76 are likely to be a good choice. A 70,000 lbf intercooled turbofan engine is large enough to make efficient use of an all-axial compression system, particularly within a geared fan configuration, but intercooling is perhaps more likely to be applied to even larger engines. The proposed optimal jet velocity ratio is actually higher than the value one would expect by using standard analytical expressions, primarily because this design variable affects core efficiency at mid-cruise due to a combination of several different subtle changes to the core cycle and core component efficiencies at this condition. The analytical expressions do not consider changes in core efficiency and the beneficial effect of intercooling on transfer efficiency, nor do they account for losses in the bypass duct and jet pipe, while a relatively detailed engine performance model, such as the one utilized in this study, does. Mission fuel results from a surrogate model are in good agreement with the results obtained from a rubberized-wing aircraft model for some of the design parameters. This indicates that it is possible to replace an aircraft model with specific fuel consumption and weight penalty exchange rates. Nevertheless, drag count exchange rates have to be utilized to properly assess changes in mission fuel for those design parameters that affect nacelle diameter.

  • 28.
    Kyprianidis, Konstantinos
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center. Cranfield University, UK.
    Rolt, Andrew
    Rolls-Royce plc, UK.
    Grönstedt, Tomas
    Chalmers University of Technology, Sweden.
    Multi-disciplinary Analysis of a Geared Fan Intercooled Core Aero-Engine2013In: Proc. ASME. 55133; Volume 2: Aircraft Engine; Coal, Biomass and Alternative Fuels; Cycle Innovations, V002T07A027. GT2013-95474, 2013Conference paper (Refereed)
    Abstract [en]

    Reduction of CO2 emissions is strongly linked with the improvement of engine specific fuel consumption, as well as the reduction of engine nacelle drag and weight. One alternative design approach to improving specific fuel consumption is to consider a geared fan combined with an increased overall pressure ratio intercooled core performance cycle. Thermal benefits from intercooling have been well documented in the literature. Nevertheless, there is very little information available in the public domain with respect to design space exploration of such an engine concept when combined with a geared fan. The present work uses a multidisciplinary conceptual design tool to analyse the option of an intercooled core geared fan aero engine for long haul applications with a 2020 entry into service technology level assumption.

    With minimum mission fuel in mind, the results indicate as optimal values a pressure ratio split exponent of 0.38 and an intercooler mass flow ratio just below 1.2 at hot-day top of climb conditions. At ISA mid-cruise conditions a specific thrust of 86m/s, a jet velocity ratio of 0.83, an intercooler effectiveness of 55% and an overall pressure ratio value of 76 are likely to be a good choice. A 70,000lbf intercooled turbofan engine is large enough to make efficient use of an all-axial compression system, particularly within a geared fan configuration, but intercooling is perhaps more likely to be applied to even larger engines.

    The proposed optimal jet velocity ratio is actually higher than the value one would expect by using standard analytical expressions primarily because this design variable affects core efficiency at mid-cruise due to a combination of several different subtle changes to the core cycle and core component efficiencies at this condition. Analytical expressions do not consider changes in core efficiency and the beneficial effect of intercooling on transfer efficiency, nor account for losses in the bypass duct and jet pipe, whilst a relatively detailed engine performance model such as the one utilised in this study does.

    Mission fuel results from a surrogate model are in good agreement with the results obtained from a rubberised-wing aircraft model for some of the design parameters. This indicates that it is possible to replace an aircraft model with specific fuel consumption and weight penalty exchange rates. Nevertheless, drag count exchange rates have to be utilised to properly assess changes in mission fuel for those design parameters that affect nacelle diameter.

  • 29.
    Kyprianidis, Konstantinos
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center. Cranfield University, UK.
    Rolt, Andrew M.
    Rolls-Royce plc.
    On the Optimisation of a Geared Fan Intercooled Core Engine Design2014In: Proc. ASME. 45653; Volume 3A: Coal, Biomass and Alternative Fuels; Cycle Innovations; Electric Power; Industrial and Cogeneration, V03AT07A018. GT2014-26064, 2014Conference paper (Refereed)
    Abstract [en]

    Reduction of CO2 emissions is strongly linked with the improvement of engine specific fuel consumption, as well as the reduction of engine nacelle drag and weight. One alternative design approach to improving specific fuel consumption is to consider a geared fan combined with an increased overall pressure ratio intercooled core performance cycle. Thermal benefits from intercooling have been well documented in the literature. Nevertheless, there is little information available in the public domain with respect to design space exploration of such an engine concept when combined with a geared fan. The present work uses a multidisciplinary conceptual design tool to further analyse the option of an intercooled core geared fan aero engine for long haul applications with a 2020 entry into service technology level assumption. The proposed design methodology is capable, with the utilised tool, of exploring the interaction of design criteria and providing critical design insight at engine-aircraft system level.

    Previous work by the authors focused on understanding the design space for this particular configuration with minimum specific fuel consumption, engine weight and mission fuel in mind. This was achieved by means of a parametric analysis, varying several engine design parameters — but only one at a time. The present work attempts to identify “globally” fuel burn optimal values for a set of engine design parameters by varying them all simultaneously. This permits the non-linear interactions between the parameters to be accounted. Special attention has been given to the fuel burn impact of the reduced HPC efficiency levels associated with low last stage blade heights.

    Three fuel optimal designs are considered, based on different assumptions. The results indicate that it is preferable to trade overall pressure ratio and pressure ratio split exponent, rather than specific thrust, as means of increasing blade height and hence reducing the associated fuel consumption penalties. It is interesting to note that even when considering the effect of HPC last stage blade height on efficiency there is still an equivalently good design at a reduced overall pressure ratio. This provides evidence that the overall economic optimum could be for a lower overall pressure ratio cycle. Customer requirements such as take-off distance and time to height play a very important role in determining a fuel optimal engine design. Tougher customer requirements result in bigger and heavier engines that burn more fuel. Higher overall pressure ratio intercooled engine cycles clearly become more attractive in aircraft applications that require larger engine sizes.

  • 30.
    Kyprianidis, Konstantinos
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center. Cranfield University.
    Rolt, Andrew M.
    Rolls-Royce plc.
    Sethi, Vishal
    Cranfield University.
    On Intercooled Turbofan Engines2013In: Progress in Gas Turbine Performance / [ed] Ernesto Benini, Rijeka, Croatia: InTech, 2013, 1st, , p. 268p. 3-24Chapter in book (Refereed)
  • 31.
    Kyprianidis, Konstantinos
    et al.
    Chalmers University, Sweden.
    Sethi, Vishal
    Cranfield University, UK.
    Ogaji, S O T
    Cranfield University, UK.
    Pilidis, Pericles
    Cranfield University, UK.
    Singh, Riti
    Cranfield University, UK.
    Kalfas, A I
    Aristotle University of Thessaloniki, Greece.
    Uncertainty in gas turbine thermo-fluid modelling and its impact on performance calculations and emissions predictions at aircraft system level2012In: Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering, ISSN 0954-4100, Vol. 226, no 2, p. 163-181Article in journal (Refereed)
    Abstract [en]

    In this article, various aspects of thermo-fluid modelling for gas turbines are described and the impact on performance calculations and emissions predictions at aircraft system level is assessed. Accurate and reliable fluid modelling is essential for any gas turbine performance simulation software as it provides a robust foundation for building advanced multi-disciplinary modelling capabilities. Caloric properties for generic and semi-generic gas turbine performance simulation codes can be calculated at various levels of fidelity; selection of the fidelity level is dependent upon the objectives of the simulation and execution time constraints. However, rigorous fluid modelling may not necessarily improve performance simulation accuracy unless all modelling assumptions and sources of uncertainty are aligned to the same level.

    A comprehensive analysis of thermo-fluid modelling for gas turbines is presented, and the fluid models developed are discussed in detail. Common technical models, used for calculating caloric properties, are compared while typical assumptions made in fluid modelling, and the uncertainties induced, are examined. Several analyses, which demonstrate the effects of composition, temperature, and pressure on caloric properties of working media for gas turbines, are presented. The working media examined include dry air and combustion products for various fuels and H/C ratios. The uncertainty induced in calculations by (a) using common technical models for evaluating fluid caloric properties and (b) ignoring dissociation effects is examined at three different levels: (i) component level, (ii) engine level, and (iii) aircraft system level. An attempt is made to shed light on the trade-off between improving the accuracy of a fluid model and the accuracy of a multi-disciplinary simulation at aircraft system level, against computational time penalties. The validity of the ideal gas assumption for future turbofan engines and novel propulsion cycles is discussed. The results obtained demonstrate that accurate modelling of the working fluid is essential, especially for assessing novel and/or aggressive cycles at aircraft system level. Where radical design space exploration is concerned, improving the accuracy of the fluid model will need to be carefully balanced with the computational time penalties involved.

  • 32.
    Kyprianidis, Konstantinos
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Skvaril, JanMälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Developments in Combustion Technology2016Collection (editor) (Refereed)
    Abstract [en]

    Over the past few decades, exciting developments have taken place in the field of combustion technology. The present edited volume intends to cover recent developments and provide a broad perspective of the key challenges that characterize the field. The target audience for this book includes engineers involved in combustion system design, operational planning and maintenance. Manufacturers and combustion technology researchers will also benefit from the timely and accurate information provided in this work. The volume is organized into five main sections comprising 15 chapters overall: - Coal and Biofuel Combustion - Waste Combustion - Combustion and Biofuels in Reciprocating Engines - Chemical Looping and Catalysis - Fundamental and Emerging Topics in Combustion Technology

  • 33.
    Kyprianidis, Konstantinos
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Skvaril, JanMälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Developments in Near-Infrared Spectroscopy2017Collection (editor) (Refereed)
    Abstract [en]

    Over the past few decades, exciting developments have taken place in the field of near-infrared spectroscopy (NIRS). This has been enabled by the advent of robust Fourier transform interferometers and diode array solutions, coupled with complex chemometric methods that can easily be executed using modern microprocessors. The present edited volume intends to cover recent developments in NIRS and provide a broad perspective of some of the challenges that characterize the field. The volume comprises six chapters overall and covers several sectors. The target audience for this book includes engineers, practitioners, and researchers involved in NIRS system design and utilization in different applications. We believe that they will greatly benefit from the timely and accurate information provided in this work.

  • 34.
    Larsson, Linda
    et al.
    Volvo Aero Corporation, Trollhättan, Sweden .
    Grönstedt, Tomas
    Chalmers University, Gothenburg, Sweden.
    Kyprianidis, Konstantinos G.
    Chalmers University, Gothenburg, Sweden.
    Conceptual Design and Mission Analysis for a Geared Turbofan and an Open Rotor Configuration2011In: Proc. ASME. 54617; Volume 1: Aircraft Engine; Ceramics; Coal, Biomass and Alternative Fuels; Wind Turbine Technology. GT2011-46451, 2011, p. 359-370Conference paper (Refereed)
    Abstract [en]

    In this multidisciplinary study a geared open rotor configuration is assessed and compared to an ultra high bypass ratio geared turbofan engine. Both designs assume a 2020 entry into service level of technology. The specific thrust level for minimizing block fuel and the resulting engine emissions for a given mission is sought. The tool used contains models that effectively capture: engine performance, mechanical and aerodynamic design, engine weight, emissions, aircraft design and performance as well as direct operating costs. The choice of specific thrust is a complex optimization problem and several disciplines need to be considered simultaneously. It will be demonstrated, through multidisciplinary analysis, that the open rotor concept can offer a substantial fuel saving potential, compared to ducted fans, for a given set of design considerations and customer requirements.

  • 35.
    Najafi Saatlou, Esmail
    et al.
    Cranfield University, UK.
    Kyprianidis, Konstantinos
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center. Cranfield University, UK.
    Sethi, Vishal
    Cranfield University, UK.
    Abu, A O
    Cranfield University, UK.
    Pilidis, Pericles
    Cranfield University, UK.
    On the trade-off between minimum fuel burn and maximum time between overhaul for an intercooled aeroengine2014In: Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering, ISSN 0954-4100, Vol. 228, no 13, p. 2424-2438Article in journal (Refereed)
    Abstract [en]

    A large variety of promising power and propulsion system concepts are being proposed to reduce carbon dioxide and other emissions. However, the best candidate to pursue is difficult to select and it is imperative that major investments are correctly targeted to deliver environmentally friendly, economical and reliable solutions. To conceive and assess gas turbine engines with minimum environmental impact and lowest cost of ownership in a variety of emission legislation scenarios and emissions taxation policies, a tool based on a techno-economic and environmental risk assessment methodology is required. A tool based on this approach has been developed by the authors. The core of the tool is a detailed and rigorous thermodynamic representation of power plants, around which other modules can be coupled (that model different disciplines such as aircraft performance, economics, emissions, noise, weight and cost) resulting in a multidisciplinary framework. This approach can be used for efficient and cost-effective design space exploration in the civil aviation, power generation, marine, and oil and gas fields. In the present work, a conceptual intercooled core aeroengine design was assessed with component technologies consistent with 2020 entry into service via a multidisciplinary optimisation approach. Such an approach is necessary to assess the trade-off between asset life, operating costs and technical specification. This paper examines the influence of fuel consumption, engine weight and direct operating costs with respect to extending the engine life. The principal modes of failure such as creep, fatigue and oxidation, are considered in the engine life estimation. Multidisciplinary optimisation, comprising the main engine design parameters, was carried out with maximum time between overhaul as the objective function. The trade-off between minimum block fuel burn and maximum engine life was examined; the results were compared against the initial engine design and an assessment was made to identify the design changes required for obtaining an improved engine design in terms of direct operating costs. The results obtained from the study demonstrate that an engine optimised for maximum time between overhaul requires a lower overall pressure ratio and specific thrust but this comes at the cost of lower thermal efficiency and higher engine production costs.

  • 36.
    Nalianda, D. K.
    et al.
    Cranfield University, Cranfield, Bedfordshire, United Kingdom.
    Kyprianidis, Konstantinos
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Sethi, V.
    Cranfield University, Cranfield, Bedfordshire, United Kingdom.
    Singh, R.
    Cranfield University, Cranfield, Bedfordshire, United Kingdom.
    Techno-economic viability assessments of greener propulsion technology under potential environmental regulatory policy scenarios2015In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 157, p. 35-50Article in journal (Refereed)
    Abstract [en]

    Sustainability of the aviation industry, as any other industry, depends on the elasticity of demand for the product and profitability through minimising operating costs. Of paramount importance is assessing and understanding the interdependency and effects of environmentally optimised solutions and emission mitigation policies.This paper describes the development and application of assessment methodologies to better understand the effects of environmental taxation/energy policies aimed at environmental pollution reduction and the future potential economic impact they may have on the adaptation of "greener" novel technologies. These studies are undertaken using a Techno-economic Environmental Risk Assessment approach. The methodology demonstrated allows the assessment of the economic viability of new technologies compared to conventional technologies, for various CO<inf>2</inf> emission taxation and fuel price scenarios. It considers relative increases in acquisition price and maintenance costs.A study undertaken as a 'proof of concept' compares a Counter Rotating Open Rotor aircraft with a conventional aircraft for short range operations. It indicates that at current fuel price and with no carbon taxation, a highly fuel efficient technology, such as the one considered, could be rendered economically unviable.The work goes on to demonstrate that in comparison to the conventional aircraft, any economic benefits that may be accrued from improvement in fuel consumption through such a technology, may well be negated through increases in acquisition price and maintenance costs. The work further demonstrates that if policy makers want to direct the industry towards greener propulsion solutions, then an increase in CO<inf>2</inf> emission taxation may be appropriate.

  • 37.
    Pascovici, Daniele S.
    et al.
    Cranfield University, UK.
    Kyprianidis, Konstantinos G.
    Cranfield University, UK.
    Colmenares Quintero, R. F.
    Cranfield University, UK.
    Ogaji, Stephen O. T.
    Cranfield University, UK.
    Pilidis, Pericles
    Cranfield University, UK.
    Weibull Distributions Applied to Cost and Risk Analysis for Aero Engines2008In: Proc. ASME. 43123; Volume 2: Controls, Diagnostics and Instrumentation; Cycle Innovations; Electric Power. GT2008-51060, 2008, p. 681-690Conference paper (Refereed)
    Abstract [en]

    This paper presents the use of Weibull formulation to the life analysis of different parts of the engine in order to estimate the cost of maintenance, the direct operating costs (DOC) and net present cost (NPC) of future type turbofan engines. The Weibull distribution is often used in the field of life data analysis due to its flexibility—it can mimic the behavior of other statistical distributions such as the normal and the exponential. The developed economic model is composed of three modules: a lifing module, an economic module and a risk module. The lifing module estimates the life of the high pressure turbine blades through the analysis of creep and fatigue over a full working cycle of the engine. The value of life calculated by the lifing is then taken as the baseline distribution to calculate the life of other important modules of the engine using the Weibull approach. Then the lower of the values of life of all the distributions is taken as time between overhaul (TBO), and used into the economic module calculations. The economic module uses the TBO together with the cost of labour and the cost of the engine (needed to determine the cost of spare parts) to estimate the cost of maintenance and DOC of the engine. In the present work five Weibull distributions are used for five important sources of interruption of the working life of the engine: Combustor, Life Limited Parts (LLP), High Pressure Compressor (HPC), General breakdowns and High Pressure Turbine (HPT). The risk analysis done in this work shows the impact of the breakdown of different parts of the engine on the NPC and DOC, the importance that each module of the engine has in its life, and how the application of the Weibull theory can help us in the risk assessment of future aero engines. A detailed explanation of the economic model is done in two other works (Pascovici et. al. [6] and Pascovici et. al. [7]), so in this paper only a general overview is done.

  • 38.
    Rahman, Moksadur
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Avelin, Anders
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Kyprianidis, Konstantinos
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Dahlquist, Erik
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    An Approach For Feedforward Model Predictive Control For Pulp and Paper Applications: Challenges And The Way Forward2017In: Paper Conference and Trade Show, PaperCon 2017: Renew, Rethink, Redefine the Future, Volume 3, TAPPI Press, 2017, Vol. 10, p. 1441-1450Conference paper (Refereed)
    Abstract [en]

    Due to the naturally varying feedstock, significant residence time, insufficient measurements and complex nature of the delignification process, producing pulp with consistent quality i.e. stable kappa number with sufficiently high yield is a challenging task that requires multi-variable process control. A wide variety of control structures, ranging from classical concepts like cascade control, feedforward, ratio control, and parallel control to more modern concepts like model-based predictive control, is used in pulp and paper industries all over the world. In this paper, a survey of model-based predictive control will be presented along with the control challenges that lie within the chemical pulping process. The potential of this control concept for overcoming the aforementioned technical challenges will also be discussed in the second part of the paper. Particular focus will be given on the use of near-infrared spectroscopy based soft-sensors coupled with dynamic process models as an enabler for feedforward model-based predictive control. Overall, the proposed control concept is expected to significantly improve process performance, in the presence of measurement noise and various complex chemical process uncertainties common in pulp and paper applications.

  • 39.
    Ramirez Camacho, Ramiro Gustavo
    et al.
    UNIFEI - Federal University of Itajubá Brazil.
    da Silva, Edna R.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Kyprianidis, Konstantinos
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Oliver, Visconti
    UNIFEI - Federal University of Itajubá Brazil.
    Cascade Optimization Using Controlled Random Search Algorithm and CFD Techniques for ORC Application2016Conference paper (Refereed)
    Abstract [en]

    The methodology for performance optimization of a cascade using CFD techniques for ORC (Organic Rankine Cycle) application are presented. The turbine ORC cascade is parameterized to achieve the maximum efficiency while using different organics fluids. The main objective of this work is to attain a maximal Cl/Cd ratio from a preliminary design. The CRSA (Controlled Random Search Algorithm) was chosen for the optimization process integrated with CFD techniques, using schemes with automatic building of parameterized geometries and meshes via "script files" interpreted by the commercial software ICEM-CFD®. Finally, for the numerical calculation of the fluid flow, the commercial software FLUENT® is used with the fluids properties, the real gases model, the turbulence model and the boundary conditions being set through "journal files". In this paper, R245fa and Toluene are used as working fluids, chosen for their characteristics curves being very different, directly influencing the behavior of the fluid during its expansion process. The results show that the methodology allows for making corrections in the initial design of the cascade shape. It will be necessary to introduce the camber function to correct for the separation of the boundary layer in the trailing edge, which is a proposal for future work.

  • 40.
    Rezek, Thiago Junqueira
    et al.
    Federal University of Itajubá, Brazil.
    da Silva, Edna R.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Ramirez Camacho, Ramiro Gustavo
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center. Federal University of Itajubá, Brazil.
    Kyprianidis, Konstantinos
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Multi-Objective Aerodynamic Optimization of an Unmanned Aerial Vehicle2016Conference paper (Other academic)
    Abstract [en]

    In the present work, a global multi-objective optimization methodology with meta-models is developed and applied for optimizing the aerodynamic performance of an unmanned aerial vehicle (UAV) airfoil. The shape of the airfoil is obtained using a parameterization scheme based on Bezier curves. The aim is to optimize the performance of a high-lift airfoil by increasing the lift force while minimizing the pitching moment generated by the integration of the viscous and pressure forces acting on the airfoil. The proposed strategy for determining the optimal design solution for maximum lift and minimum moment is based on the construction of meta-models in conjunction with robust optimization algorithms. In more detail, a direct multi-objective optimization methodology using the concept of Pareto front is utilized. A relatively small number of design points is evaluated and their function values are stored in a database for meta-model construction. Radial Basis Functions such as multi-quadrics are used for the meta-model construction. The overall optimization process is integrated with Computation Fluid Dynamics techniques, using automatic schemes that build on parameterized airfoil geometries to construct a suitable mesh through scripts. Tcl/Tk language is employed along with the commercial software ICEM-CFD in batch mode. For the numerical calculation of the flow, the software FLUENT is used with fluid properties, turbulence model and boundary conditions set also in batch mode. It is demonstrated that the proposed methodology allows to develop realistic high performance airfoil conceptual designs, with relatively little computational effort. The methodology is generic and can be applied in a variety of problems related to fluid mechanics and heat transfer.

  • 41.
    Roberto Caetano, N.
    et al.
    Aerospace Engineering, Department of Mechanical Engineering, Federal University of Santa Maria, Brazil.
    Schmitz Venturini, M.
    Aerospace Engineering, Department of Mechanical Engineering, Federal University of Santa Maria, Roraima Avenue, 1000, Santa Maria, RS, Brazil.
    Roman Centeno, F.
    Department of Mechanical Engineering, Federal University of Rio Grande do Sul, Brazil.
    Katiuscia Lemmertz, C.
    Department of Mechanical Engineering, Federal University of Rio Grande do Sul, Sarmento Leite Street, 425, Porto Alegre, RS, Brazil.
    Kyprianidis, Konstantinos
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Assessment of mathematical models for prediction of thermal radiation heat loss from laminar and turbulent jet non-premixed flames2018In: Thermal Science and Engineering Progress, ISSN 2451-9049, Vol. 7, p. 241-247Article in journal (Refereed)
    Abstract [en]

    Radiation plays an important role in several processes, being of particular interest to energy efficiency and safety of staff and facilities, mainly in the aerospace industry. In this context, along the last years mathematical models have been developed and reported in the literature aiming to obtain reliable predictions of thermal radiation in combustion applications. Some simplified models consider that thermal radiation emmited by a flame is mainly governed by the flame temperature, while other ones also account for the contribution of the combustion products. On the other hand, more detailed models include both flame geometry and composition. Many efforts have been made by several scientists in order to develop these models, however, there is no validation applied in different operating conditions found in the literature. Thus, the novelty brought by this work consists in an assessment on the comparison between the experimental data of thermal radiation emitted by jet non-premixed flames and the results obtained by calculations applying these models on several flame conditions, encompassing a wide range of applications: laminar and turbulent flames, buoyancy and momentum-driven flames, low-carbon and high-carbon fuels. Such assessments are important to assist combustion system designers on selecting the most adequate thermal radiation model during the project of a combustion system or process. The results found in the current investigation pointed out to a good agreement between experimental data and predictions obtained by detailed models, which consider flame geometry and radiative properties. On the other hand, simplified models must be avoided if accurate predictions of radiation are being sought, despite this, they can be employed as engineering tools for risk analysis, once, in general, they provided higher predictions when compared to the experiments, resulting in a safety factor to engineers and designers.

  • 42.
    Samuelsson, Sebastian
    et al.
    Chalmers University of Technology, Sweden.
    Kyprianidis, Konstantinos
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Grönstedt, Tomas
    Chalmers University of Technology, Sweden.
    Consistent Conceptual Design and Performance Modelling of Aero Engines2015In: Proceedings of the ASME Turbo Expo, 2015, Vol. 3, p. V003T06A017-Conference paper (Refereed)
    Abstract [en]

    During the conceptual design process of an engine, a thermodynamic cycle is initially defined. This is done to ensure that all aircraft requirements, defined in a number of discrete operating points, can be met. Critical component requirements can then be screened off from these operating points underpinning the conceptual design process. As an example, this has traditionally meant that aerodynamic sizing for low specific thrust turbofan engines occurs at top-of-climb and mechanical and temperature constraints are set at take-off.

    By providing additional parameters indicating the level of technology assumed, such as diffusion factors and stage loadings, a basic geometric representation of the engine can be mapped out as part of the conceptual design process. However, by choosing the parameters representing the component technology levels explicitly, the ability to trade efficiency for weight, or efficiency for cost, becomes less potent. In general, an explicit parameter choice will mean that a suboptimal solution is found.

    Hence, it makes sense to develop methods that allow including these technology parameters into the conceptual design and performance modeling process in a consistent way. If, for instance, component efficiency is modeled based on turbomachinery stage loading, including the stage loading parameters into the optimization means that the efficiency must be updated based on the stage loading variation. In general, a consistent method requires that conceptual design input is collected in a number of performance operating points, transferred into the conceptual design process and that output from the conceptual design process is returned to the optimizer.

    To illustrate the consistent conceptual design and performance modeling process, turbomachinery component models are included in the paper, interrelating polytropic efficiency, Reynolds number, size effects and component entry into service. These equations are solved consistently in the conceptual design and performance modeling to establish an optimum year 2020 engine. The method is then further illustrated by comparing the year 2020 engine with two year 2030 engines. The first year 2030 engine is established by an optimization assuming fixed polytropic turbomachinery efficiencies. The other case is defined by assuming the same engine architecture, i.e., the same number of turbomachinery stages as the year 2020 engine. In this case, the efficiency modeling is done using a consistent conceptual design optimization. The consistent optimization produced a more efficient engine despite the fact that the stage numbers were limited to the year 2020 configuration. The benefit is obtained by more thoroughly exploring the pressure ratio distribution between the engine components, as a result of the consistent optimization methodology.

  • 43.
    Skvaril, Jan
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Kyprianidis, Konstantinos
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Avelin, Anders
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Odlare, Monica
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Dahlquist, Erik
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Application of Near Infrared Spectroscopy for Rapid Characterization of Feedstock Material in Pulp and Paper Industry2015In: Book of abstracts, 2015Conference paper (Refereed)
    Abstract [en]

    Pulp digesters can be continuous or batch reactors with significant residence time which are fed with woodchips and cooking chemicals. They deliver the pulp-fibers that are used in the production of paper, as well as black liquor that is combusted in the chemical recovery boiler. The possibility to measure what is happening inside the digester is limited. The most important quality properties of the feedstock material is content of lignin, which is being dissolved during the process, and related material reactivity. Pulp quality after the process is measured by Kappa number which is a measure of residual lignin in the pulp. One of the biggest challenges in pulp production process is the great variability in feedstock material properties. If the process is not adjusted by well-timed and appropriate operational control measures i.e. control of inlet and outlet flows and setting of the cooking recipe, it will result in the large variations in Kappa number, lower fiber quality or excess use of environmentally harmful cooking chemicals. This becomes particularly important during the swing between softwood and hardwood as part of meeting the final paper product quality requirements. Therefore, a rapid method that is capable of continuous feedstock material characterization is required.Near infrared (NIR) spectroscopy can be used for non-destructive characterization of the feedstock material. In this study, both Fourier transform and grating NIR spectrophotometers were used for NIR absorbance spectra acquisition. Each spectrum was recorded in the range between 700 and 2500 nm. During the calibration of spectra of various wood species with known lignin content, wood samples were placed on a tray so that the tray may move horizontally in a reciprocating manner underneath the sensor while maintaining the constant distance between the sensor and sample. This was done in order to simulate the movement of a real conveyor belt as used for transporting feedstock to the digester. In the on-line application the NIR meter is situated above the conveyor belt that wood up to the digester.Spectral data were pretreated with different methods such as normalization, scatter correction, smoothing, first and second derivative (Savitzky-Golay algorithm), selection of different spectral ranges and its combinations. Mathematical models to estimate lignin content were constructed using Partial Least Square Regression (PLS-R) and Principle component regression (PCR) statistical methods. Response data for model build-up were determined in the chemical laboratory according to standardized procedures including test repetitions. Different combinations of NIR instrument used, pre-treatment methods and statistical methods were evaluated in order to find the model with the best prediction performance.Results are promising and demonstrate that it is possible to characterize the lignin content and reactivity of the feedstock material by NIR spectrophotometers with reasonable prediction model performance. Improved prediction can be obtained if only selected spectral ranges are included as an input for statistical modelling; similarly using derivatives is better than using the raw spectrum. In the next step, developed statistical models for rapid lignin content prediction will be used as a feed-forward input for dynamic process control.

  • 44.
    Skvaril, Jan
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Kyprianidis, Konstantinos
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Avelin, Anders
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Odlare, Monica
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Dahlquist, Erik
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Effect of wood chip moving velocity on NIR spectra acquisition and model calibration for lignin quantificationManuscript (preprint) (Other academic)
  • 45.
    Skvaril, Jan
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Kyprianidis, Konstantinos
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Avelin, Anders
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Odlare, Monica
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Dahlquist, Erik
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Fast Determination of Fuel Properties in Solid Biofuel Mixtures by Near Infrared Spectroscopy2017In: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 105, p. 1309-1317Article in journal (Refereed)
    Abstract [en]

    This paper focuses on the characterization of highly variable biofuel properties such as moisture content, ash content and higher heating value by near-infrared (NIR) spectroscopy. Experiments were performed on different biofuel sample mixtures consisting of stem wood chips, forest residue chips, bark, sawdust, and peat. NIR scans were performed using a Fourier transform NIR instrument, and reference values were obtained according to standardized laboratory methods. Spectral data were pre-processed by Multiplicative scatter correction correcting light scattering and change in a path length for each sample. Multivariate calibration was carried out employing Partial least squares regression while absorbance values from full NIR spectral range (12,000–4000 cm-1), and reference values were used as inputs. It was demonstrated that different solid biofuel properties can be measured by means of NIR spectroscopy. The accuracy of the models is satisfactory for industrial implementation towards improved process control. 

  • 46.
    Skvaril, Jan
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Kyprianidis, Konstantinos
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Avelin, Anders
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Odlare, Monica
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Dahlquist, Erik
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Fast Determination of Lignin Content in Feedstock Material for Pulping Process Monitoring and Optimization2015In: ICAVS 8 - Abstracts poster, 2015, p. 556-557Conference paper (Refereed)
    Abstract [en]

    Pulping process is delivering pulp fibers which are further used in the production of paper. The reactor is fed with feedstock material in the form of wood chips. Moreover, cooking chemicals are brought at several points into the reactor. Previous studies have shown that the knowledge of the feedstock material properties which are highly variable is limited. One of the most important parameters is the lignin content, which has to be dissolved, this requires a significant residence time. The residual lignin in the resulting pulp after the process is measured in the form of Kappa number. Inappropriate application of cooking chemicals could lead to large variations in the Kappa number, low fiber quality and other issues. Therefore continuous characterization of the feedstock material is required. One of the available methods for nondestructive characterization of feedstock material is NIR spectroscopy. Presented study is conducted in order to assess the possibility of determining lignin content using NIR method. The spectroscopy workflow consist of four major steps i.e. sample preparation, spectral data acquisition, data pre-processing and multivariate calibration. We used test samples from 13 different tree species, which were tested in the form of wood chips, pulverized wood and mixture of both. Acquired spectral data were pre-processed mainly by second derivative and standard normal variate transformation. PLS regression with full cross validation was used for the development of a calibration model based on selected wavelengths. Acquisition of reference variable has been done according to standardized procedures and it represents the total amount of lignin in the sample.

    The results of lignin characterization in feedstock material by NIR are very promising. The resulting PLS regressionmodel includes 2-factors and uses 16 predicting variables, resulting in R2 = 0,975, RMSE = 0,885 wt%. In the next step, presented work will be improved by applying large amount of samples, independent validation data set and by simulation of conveyor belt movements. The objective of this research is to test the NIR method at a real pulp digester, in order to improve monitoring andoptimization of the process. Furthermore, continuous characterization of the feedstock materials is intended to be used for the improvement of the control process. The measured lignin content will be compared to the content calculated within the pulp digester physical model and the Kappa number. This will be used for improving the digester physical model accuracy and as an input to advanced model based control, where the correlation will be made not only to lignin content but also with the feedstock material reactivity.

  • 47.
    Skvaril, Jan
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Kyprianidis, Konstantinos
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Avelin, Anders
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Odlare, Monica
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Dahlquist, Erik
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Multivariate analysis models for wood properties combined with Open Modelica model for process performance monitoring2015In: IFAC Proceedings Volumes (IFAC-PapersOnline), 2015, Vol. 48:1, p. 898-899Conference paper (Other (popular science, discussion, etc.))
    Abstract [en]

    To perform advanced model based control it is important to know what is fed into a system such as a waste or biomass fired boiler or a pulp digester. In this paper, we present correlations between the lignin content of different types of wood chips and their Near-infrared (NIR) spectra. The Principal Component Regression (PCR) method is used for deriving the correlation, as well as selecting certain wave lengths. Analysis is made including different parts of the spectra in the wave length range 700 – 2500 nm. The model is then used as input to an Open Modelica pulp digester model to tune the reactivity constant of the dissolution of lignin. The lignin content of wood-chips is determined on-line through the NIR measurement at the feed to the digester. Simulations are carried out to determine the content of residual lignin on fibers at the exit (continuous digester) or at the end of a cook (batch digester). By comparing the deviation between predicted values and actual measured values the reactivity constant of the lignin is determined. The regression can be made to the NIR spectrum aside of the lignin content as such. The original content of lignin together with reactivity may then be used for optimized on-line control of the digester. It can also be used for diagnostic purposes with regard to process issues like hang-ups or channeling, as well as possible sensor faults and data reconciliation.

  • 48.
    Skvaril, Jan
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Kyprianidis, Konstantinos
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Avelin, Anders
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Odlare, Monica
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Dahlquist, Erik
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Rapid Determination of Selected Compounds in Waste-based Fuel by Near Infrared Spectroscopy2015In: Book of abstracts, 2015Conference paper (Refereed)
    Abstract [en]

    Composition of the waste-based fuel intended for incineration has substantial effect on combustion process performance and formation of environmentally harmful emissions. Fuel composition vary significantly depending on the material source, waste sorting and recycling procedures and other waste pretreatment methods. In general, it typically contains paper, plastics, wood, textile, other organic material and further undesired substances including glass and metals. The knowledge of actual composition of the material fed into the boiler is limited to the direct or indirect continuous moisture content measurements and periodic fuel sampling providing elementary composition. This information is not sufficient for process control and performance optimization, particularly when considering strongly heterogeneous fuel feed. Therefore a rapid and reliable technique for fuel characterization is needed.The work presented here is focused to the quantitative determination of selected plastic materials and glass content. Incomplete combustion of different plastics may lead to the formation of carbon monoxide, hydrogen-cyanides, acid compounds and aromatic hydrocarbons etc. If the waste contains chlorine then highly chlorinated polycyclic compounds such as dioxins and furans may be formed. Plastics often contain flame retardants which can also contribute to production of harmful emissions. On the other hand, the highly corrosive deposits of alkali chlorides and other compounds may be formed on the heat exchangers, this lowers the heat transfer and boiler efficiency and decrease life-time of the equipment. Moreover, increased content of glass in the fuel supports the formation of agglomerates in the fuel bed, defluidization of the bed or ash removal problems which result in malfunction or failure of the combustion equipment.Near infrared (NIR) spectroscopy can be used for non-destructive quantitative determination of plastics and glass in waste-based fuel. Experimental work was performed on two types of spectrophotometers i.e. grating and Fourier transform instruments. Samples of known content of glass and different plastics were placed on a moving tray that reciprocated horizontally back and forth underneath the NIR sensor. This was done in order to replicate online application where the NIR spectrophotometer is places above the conveyor belt that transport the fuel to the boiler.Spectra were recorded in the range between 700 and 2500 nm. Acquired spectral data were pretreated with different methods such as normalization, scatter correction, smoothing, first and second derivative (Savitzky-Golay algorithm), selection of different spectral ranges and its combinations. Mathematical models to estimate content of glass and different plastics were constructed using Partial Least Square Regression (PLS-R) and Principle component regression (PCR) statistical methods. Different combinations of spectrophotometer type, pre-treatment methods and statistical methods were evaluated in order to find the model with the best prediction performance.Results prove the potential of the method to quantitatively determine the content of different types of plastics as well as glass with reasonable prediction accuracy. The ultimate goal of this research is to test the method at a real industrial boiler in order to improve process monitoring and control.

  • 49.
    Skvaril, Jan
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Kyprianidis, Konstantinos
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Avelin, Anders
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Odlare, Monica
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Dahlquist, Erik
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Utilization of Near Infrared (NIR) Spectrometry for Detection of Glass in the Waste-based Fuel2015In: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 75, p. 734-741Article in journal (Refereed)
    Abstract [en]

    This paper presents the results of experimental measurements and multivariate statistical modeling concerning detection of soda-lime glass using near infrared (NIR) spectrometry technique. The purpose is to test if the glass is quantitatively detectable in a waste-based material and to assess what method of spectral data pretreatment is the most suitable in order to develop prediction models. The experiments were performed on six test samples containing a specific amount of glass distributed in background material. Pretreatment methods such as normalization and first and second derivatives were applied on the acquired absorbance spectral data. Principal component analysis (PCA) was employed in order to describe the relationship between pretreated data and the amount of glass in the test samples. Subsequently, principal component regression (PCR) was utilized for the development of prediction models. The results from the models show strong correlation between the pretreated data and the glass content. The most promising results were obtained from the model based on 1st derivative pretreatment when only absorbance spectral data from selected wavelengths are included. 

  • 50.
    Skvaril, Jan
    et al.
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Kyprianidis, Konstantinos
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Avelin, Anders
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Sandberg, Jan
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Erik, Dahlquist
    Mälardalen University, School of Business, Society and Engineering, Future Energy Center.
    Experimental investigation of part load operation of a full-scale biomass-fired fluidized bed boilerManuscript (preprint) (Other academic)
12 1 - 50 of 57
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