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  • 1.
    Aslanidou, Ioanna
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi. University of Oxford, United Kingdom.
    Rosic, Budimir
    University of Oxford, United Kingdom.
    Aerothermal Performance of Shielded Vane Design2017Ingår i: Journal of turbomachinery, ISSN 0889-504X, E-ISSN 1528-8900, Vol. 139, nr 11, artikel-id 111003Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper presents an experimental investigation of the concept of using the combustor transition duct wall to shield the nozzle guide vane leading edge. The new vane is tested in a high-speed experimental facility, demonstrating the improved aerodynamic and thermal performance of the shielded vane. The new design is shown to have a lower average total pressure loss than the original vane, and the heat transfer on the vane surface is overall reduced. The peak heat transfer on the vane leading edge–endwall junction is moved further upstream, to a region that can be effectively cooled as shown in previously published numerical studies. Experimental results under engine-representative inlet conditions showed that the better performance of the shielded vane is maintained under a variety of inlet conditions.

  • 2.
    Aslanidou, Ioanna
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Rosic, Budimir
    University of Oxford, United Kingdom.
    Effect of the Combustor Wall on the Aerothermal Field of a Nozzle Guide Vane2018Ingår i: Journal of turbomachinery, ISSN 0889-504X, E-ISSN 1528-8900, Vol. 140, nr 5, artikel-id 051010Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In gas turbines with can combustors the trailing edge of the combustor transition duct wall is found upstream of ev- ery second vane. This paper presents an experimental and numerical investigation of the effect of the combustor wall trailing edge on the aerothermal performance of the nozzle guide vane. In the measurements carried out in a high speed experimental facility, the wake of this wall is shown to in- crease the aerodynamic loss of the vane. On the other hand, the wall alters secondary flow structures and has a protective effect on the heat transfer in the leading edge-endwall junc- tion, a critical region for component life. The different clock- ing positions of the vane relative to the combustor wall are tested experimentally and are shown to alter the aerothermal field. The experimental methods and processing techniques adopted in this work are used to highlight the differences be- tween the different cases studied. 

  • 3.
    Aslanidou, Ioanna
    et al.
    University of Oxford, United Kingdom.
    Rosic, Budimir
    University of Oxford, United Kingdom.
    Kanjirakkad, Vasudevan
    University of Sussex, United Kingdom.
    Uchida, Sumiu
    Mitsubishi Heavy Industries, Japan.
    Leading Edge Shielding Concept in Gas Turbines With Can Combustors2012Ingår i: Journal of turbomachinery, ISSN 0889-504X, E-ISSN 1528-8900, Vol. 135, nr 2Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The remarkable developments in gas turbine materials and cooling technologies haveallowed a steady increase in combustor outlet temperature and, hence, in gas turbine efficiencyover the last half century. However, the efficiency benefits of higher gas temperature,even at the current levels, are significantly offset by the increased losses associatedwith the required cooling. Additionally, the advancements in gas turbine cooling technologyhave introduced considerable complexities into turbine design and manufacture.Therefore, a reduction in coolant requirements for the current gas temperature levels isone possible way for gas turbine designers to achieve even higher efficiency levels. Theleading edges of the first turbine vane row are exposed to high heat loads. The high coolantrequirements and geometry constraints limit the possible arrangement of the multiplerows of film cooling holes in the so-called showerhead region. In the past, investigatorshave tested many different showerhead configurations by varying the number of rows, inclinationangle, and shape of the cooling holes. However, the current leading edge coolingstrategies using showerheads have not been shown to allow a further increase inturbine temperature without the excessive use of coolant air. Therefore, new coolingstrategies for the first vane have to be explored. In gas turbines with multiple combustorchambers around the annulus, the transition duct walls can be used to shield, i.e., to protect,the first vane leading edges from the high heat loads. In this way, the stagnationregion at the leading edge and the showerhead of film cooling holes can be completelyremoved, resulting in a significant reduction in the total amount of cooling air that is otherwiserequired. By eliminating the showerhead the shielding concept significantly simplifiesthe design and lowers the manufacturing costs. This paper numerically analyzes the potentialof the leading edge shielding concept for cooling air reduction. The vane shape wasmodified to allow for the implementation of the concept and nonrestrictive relative movementbetween the combustor and the vane. It has been demonstrated that the coolant flowthat was originally used for cooling the combustor wall trailing edge and a fraction of thecoolant air used for the vane showerhead cooling can be used to effectively cool both thesuction and the pressure surfaces of the vane.

  • 4.
    Aslanidou, Ioanna
    et al.
    University of Oxford, United Kingdom.
    Rosic, Budimir
    University of Oxford, United Kingdom.
    Kanjirakkad, Vasudevan
    University of Sussex, United Kingdom.
    Uchida, Sumiu
    Mitsubishi Heavy Industries, Japan.
    Leading edge shielding concept in gas turbines with can combustors2012Konferensbidrag (Refereegranskat)
  • 5.
    Aslanidou, Ioanna
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Zaccaria, Valentina
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Pontika, E.
    Aristotle University of Thessaloniki, Thessaloniki, Greece.
    Zimmerman, Nathan
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Kalfas, A. I.
    Aristotle University of Thessaloniki, Thessaloniki, Greece.
    Kyprianidis, Konstantinos
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Teaching gas turbine technology to undergraduate students in Sweden2018Ingår i: Proceedings of the ASME Turbo Expo, American Society of Mechanical Engineers (ASME) , 2018, Vol. 6Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper addresses the teaching of gas turbine technology in a third-year undergraduate course in Sweden and the challenges encountered. The improvements noted in the reaction of the students and the achievement of the learning outcomes is discussed. The course, aimed at students with a broad academic education on energy, is focused on gas turbines, covering topics from cycle studies and performance calculations to detailed design of turbomachinery components. It also includes economic aspects during the operation of heat and power generation systems and addresses combined cycles as well as hybrid energy systems with fuel cells. The course structure comprises lectures from academics and industrial experts, study visits, and a comprehensive assignment. With the inclusion of all of these aspects in the course, the students find it rewarding despite the significant challenges encountered. An important contribution to the education of the students is giving them the chance, stimulation, and support to complete an assignment on gas turbine design. Particular attention is given on striking a balance between helping them find the solution to the design problem and encouraging them to think on their own. Feedback received from the students highlighted some of the challenges and has given directions for improvements in the structure of the course, particularly with regards to the course assignment. This year, an application developed for a mobile phone in the Aristotle University of Thessaloniki for the calculation of engine performance will be introduced in the course. The app will have a supporting role during discussions and presentations in the classroom and help the students better understand gas turbine operation. This is also expected to reduce the workload of the students for the assignment and spike their interest.

  • 6.
    Aslanidou, Ioanna
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Zaccaria, Valentina
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Rahman, Moksadur
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Oostveen, Mark
    Micro Turbine Technology bv, Eindhoven, Netherlands.
    Olsson, Tomas
    Mälardalens högskola, Akademin för innovation, design och teknik, Inbyggda system. RISE SICS, Västerås, Sweden.
    Kyprianidis, Konstantinos
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Towards an Integrated Approach for Micro Gas Turbine Fleet Monitoring, Control and Diagnostics2018Konferensbidrag (Refereegranskat)
    Abstract [en]

    Real-time engine condition monitoring and fault diagnostics results in reduced operating and maintenance costs and increased component and engine life. Prediction of faults can change the maintenance model of a system from a fixed maintenance interval to a condition based maintenance interval, further decreasing the total cost of ownership of a system. Technologies developed for engine health monitoring and advanced diagnostic capabilities are generally developed for larger gas turbines, and generally focus on a single system; no solutions are publicly available for engine fleets. This paper presents a concept for fleet monitoring finely tuned to the specific needs of micro gas turbines. The proposed framework includes a physics-based model and a data-driven model with machine learning capabilities for predicting system behaviour, combined with a diagnostic tool for anomaly detection and classification. The integrated system will develop advanced diagnostics and condition monitoring for gas turbines with a power output under 100 kW.

  • 7.
    Aslanidou, Ioanna
    et al.
    Cranfield University, United Kingdom.
    Zachos, Pavlos K.
    Cranfield University, United Kingdom.
    Pachidis, Vassilios
    Cranfield University, United Kingdom.
    Singh, Riti
    Cranfield University, United Kingdom.
    A physically enhanced method for sub-idle compressor map generation and representation2010Ingår i: Proceedings of the ASME Turbo Expo, Glasgow, United Kingdom, 2010Konferensbidrag (Refereegranskat)
  • 8.
    Aslanidou, Ioanna
    et al.
    Cranfield University, United Kingdom.
    Zachos, Pavlos K.
    Cranfield University, United Kingdom.
    Pachidis, Vassilios
    Cranfield University, United Kingdom.
    Singh, Riti
    Cranfield University, United Kingdom.
    Sub-idle & Relight Performance Modelling; A fully parametrical method for sub-idle compressor maps generation2009Konferensbidrag (Övrigt vetenskapligt)
  • 9.
    Kavvalos, Mavroudis
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Xin, Zhao
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Schnell, Rainer
    German Aerospace Center (DLR), Institute of Propulsion Technology, Cologne, Germany.
    Aslanidou, Ioanna
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Kalfas, Anestis
    Department of Mechanical Engineering, Aristotle University of Thessaloniki, Greece.
    Kyprianidis, Konstantinos
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    A Modelling Approach of Variable Geometry for Low Pressure Ratio Fans2019Ingår i: International Symposium on Air Breathing Engines, ISABE 2019, Canberra, Australia, 23 - 27 September 2019 Paper No. ISABE-2019-24382, 2019Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper presents the development and application of a modelling approach of variable geometry conceptsfor low pressure ratio fans; namely Variable Area Nozzle and Variable Pitch Fan. An enhanced approachfor Outlet Guide Vane pressure loss predictions and an aerothermodynamic analysis of variable pitchconcept are developed and integrated into a multi-disciplinary conceptual engine design framework. Astreamline curvature algorithm is deployed for the derivation of the off-design fan performance map,alleviating scaling issues from higher pressure ratio fan designs. Correction deltas are derived through thevariable pitch analysis for calculating the re-shaped off-design fan performance map. The aforementionedvariable geometry concepts are evaluated in terms of surge margin at engine and aircraft level for a lowpressure ratio aft-fan of a hybrid-electric configuration. Performance assessments carried out suggest thata +8° closing of fan blade cascades leads to a 33% surge margin improvement (with reference being thesurge margin without variable geometry) compared to a 25% improvement achieved by +20% opening thenozzle area at end of runway take-off conditions. Although weight and complexity implications of variablegeometry are not considered, the integrated modelling approach is shown to be able to assess and comparesuch novel engine technologies for low pressure ratio fans in terms of operability.

  • 10.
    Kladovasilakis, Nikolaos
    et al.
    Aristotle Univ Of Thessaloniki, Greece.
    Efstathiadis, Theofilos
    Aristotle Univ Of Thessaloniki.
    Aslanidou, Ioanna
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Kalfas, Anestis
    Aristotle Univ Of Thessaloniki.
    Rotor Blade Design of an Axial Turbine using Non-Ideal Gases with Low Real-Flow Effects2017Ingår i: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 142, s. 1127-1132Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This study aims to describe a design methodology for supersonic rotor blade geometry, depending on the working fluid, for a low enthalpy Organic Rankine Cycle (ORC) system. Thus, the working fluid is a non-ideal gas with low impact of real flow effects. An innovate algorithm was developed, in order to generate the two-dimensional geometry of the rotor blade, for various working media. A design method, based on the principle of vortex flow field, was used for the blading design and, for the design of supersonic blades, the method of characteristics was selected as the most optimum. The geometry was tested using a commercial simulation software that uses a pressure-based solving algorithm named SIMPLE (Semi-implicit Method for Pressure-Linked Equations). Key advantages of this procedure are both its simplicity and precision of the results.

    The above procedure was applied for three working fluids, indicatively isobutane (R-600a), tetrafluroethane (R134a) and a mixture of 15% isobutane – 85% isopentane. Considering the ratio of specific heat capacities as constant, which is a realistic assumption for the operating conditions of these systems, the algorithm produces three different blade geometries. Results comparison indicates that every working fluid, for the same operating conditions and for the same design options, has a significantly differentiated geometry of the two-dimensional blade. Finally, the calculated total to total isentropic efficiency, for these rotor blades, is almost 92%. 

  • 11.
    Luque, Salvador
    et al.
    University of Oxford, United Kingdom.
    Kanjirakkad, Vasudevan
    University of Sussex, United Kingdom.
    Aslanidou, Ioanna
    University of Oxford, United Kingdom.
    Lubbock, Roderick
    University of Oxford, United Kingdom.
    Rosic, Budimir
    University of Oxford, United Kingdom.
    Uchida, Sumiu
    Mitsubishi Heavy Industries, Japan.
    A New Experimental Facility to Investigate Combustor-Turbine Interactions in Gas Turbines With Multiple Can Combustors2015Ingår i: Journal of engineering for gas turbines and power, ISSN 0742-4795, E-ISSN 1528-8919, Vol. 137, nr 5Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper describes a new modular experimental facility that was purpose-built to investigateflow interactions between the combustor and first stage nozzle guide vanes (NGVs)of heavy duty power generation gas turbines with multiple can combustors. The first stageturbine NGV is subjected to the highest thermal loads of all turbine components andtherefore consumes a proportionally large amount of cooling air that contributes detrimentallyto the stage and cycle efficiency. It has become necessary to devise novel coolingconcepts that can substantially reduce the coolant air requirement but still allow theturbine to maintain its aerothermal performance. The present work aims to aid this objectiveby the design and commissioning of a high-speed linear cascade, which consists oftwo can combustor transition ducts and four first stage NGVs. This is a modular nonreactiveair test platform with engine realistic geometries (gas path and near gas path), coolingsystem, and boundary conditions (inlet swirl, turbulence level, and boundary layer).The paper presents the various design aspects of the high pressure (HP) blow down typefacility, and the initial results from a wide range of aerodynamic and heat transfermeasurements under highly engine realistic conditions.

  • 12.
    Luque, Salvador
    et al.
    University of Oxford, United Kingdom.
    Kanjirakkad, Vasudevan
    University of Sussex, United Kingdom.
    Aslanidou, Ioanna
    University of Oxford, United Kingdom.
    Lubbock, Roderick
    University of Oxford, United Kingdom.
    Rosic, Budimir
    University of Oxford, United Kingdom.
    Uchida, Sumiu
    Mitsubishi Heavy Industries, Japan.
    A New Experimental Facility to Investigate Combustor-Turbine Interactions in Gas Turbines With Multiple Can Combustors2014Konferensbidrag (Refereegranskat)
  • 13.
    Papagianni, Andromachi
    et al.
    Aristotle University of Thessaloniki, Thessaloniki, Greece.
    Kavvalos, Mavroudis
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Aslanidou, Ioanna
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Kyprianidis, Konstantinos
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Kalfas, Anestis
    Aristotle University of Thessaloniki, Thessaloniki, Greece.
    Conceptual Design of a Hybrid Gas Turbine - Solid Oxide Fuel Cell System for Civil Aviation2019Konferensbidrag (Refereegranskat)
    Abstract [en]

    A conceptual design of a hybrid Gas Turbine - Solid Oxide Fuel Cell (SOFC) system is presented for civil aviation applications. The system operates using hydrogen as fuel, for the aircraft’s propulsion, while at the same time produces electrical energy in the fuel cell. Hydrogen is produced during flight by reformation of methane. The motivation of the study is to investigate hydrogen’s use for aviation purposes, so the hybrid system’s operation characteristics need to be examined. A configuration is designed, where a SOFC and the burner is modeled as one and simulated, in a modern multidisciplinary programming environment, in order to analyze the thermodynamic characteristics of the hybrid system. The fuel cell sets into motion when the aircraft reaches top of climb. During operation, liquefied natural gas is converted to hydrogen in the fuel cell and part of it is used to produce electrical energy while the rest for combustion. To determine the efficiency of the system, its performance was simulated using two scenarios, one for longhaul flights and one for short-haul flights. Comparing the results, for long-haul flights, the hybrid system presents a reduction in fuel consumption and an increase in thermal efficiency. For flights of a short range, the existing conditions in the fuel cell inlet were found to be prohibitive for it’s operation and the use of the hybrid system ineffective. For the system’s efficiency, the larger the pressure in the SOFC’s inlet the better. However, SOFC’s pressure limits restrict the pressure range and the cell’s use only during flight. Concluding, according to the study’s results, the hybrid system can operate in flight conditions, making the use of hydrogen in civil aviation possible. As a result, a 12% and 35% benefit is achieved, in fuel saving and thermal efficiency respectively.

  • 14.
    Pontika, E. C.
    et al.
    Aristotle University, Thessaloniki, Greece.
    Kalfas, A. I.
    Aristotle University, Thessaloniki, Greece.
    Aslanidou, Ioanna
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Aeroengines: Multi-platform application for aero engine simulation and compressor map operating point prediction2019Ingår i: Proceedings of the ASME Turbo Expo, American Society of Mechanical Engineers (ASME) , 2019Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper presents the development of AeroEngineS (Aircraft Engine Simulation), a multi-platform app with graphical user interface for aero engine simulation and compressor map operating point prediction. Gas turbine performance simulation is a crucial part of the design process. It provides information about the required operating conditions of all the components and the overall performance of the engine so that engineers can determine whether the current engine configuration meets the performance requirements. Some gas turbine simulation programs have been developed in the last decades, however, there was a lack of an open-source, lightweight, user-friendly, but still very accurate, application which would be easily accessible from all platforms. AeroEngineS can be used as a user-friendly preliminary design tool, since, during this design phase, details about the geometry are not known yet. The main aim is to calculate simply and quickly the basic parameters of the thermodynamic cycle and the performance, in order to determine which design is able to meet the required specifications. AeroEngineS constitutes a free and simple app which can primarily serve educational purposes as it is easily accessible by students from any platform to assist them in aero engine technology courses. Secondarily, it has the potential to be used even by engineers as a quick tool accessible from all devices. The app consists of two basic stand-alone functions. The first function is aero engine simulation at Design Point which solves thermodynamic calculations. The second function is compressor map operating point prediction using a novel method of combining scaling techniques and Artificial Neural Networks.

  • 15. Sampath, S
    et al.
    Pellegrini, A
    Aslanidou, Ioanna
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Pilidis, P
    VSTOL Thrust Vectoring and Balancing: Degradation Mitigation Strategies2019Konferensbidrag (Refereegranskat)
  • 16.
    Winn, Olivia
    et al.
    Mälardalens högskola.
    Sivaram, Kiran Thekkemadathil
    Mälardalens högskola.
    Aslanidou, Ioanna
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Skvaril, Jan
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Kyprianidis, Konstantinos
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Near-infrared spectral measurements and multivariate analysis for predicting glass contamination of refuse-derived fuel2017Ingår i: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 142, s. 943-949Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper investigates how glass contamination in refuse-derived fuel can be quantitatively detected using near-infrared spectroscopy. Near-infrared spectral data of glass in four different background materials were collected, each material chosen to represent a main component in municipal solid waste; actual refuse-derived fuel was not tested. The resulting spectra were pre- processed and used to develop multi-variate predictive models using partial least squares regression. It was shown that predictive models for coloured glass content are reasonably accurate, while models for mixed glass or clear glass content are not; the validated model for coloured glass content had a coefficient of determination of 0.83 between the predicted and reference data, and a root- mean-square error of validation of 0.64. The methods investigated in this paper show potential in predicting coloured glass content in different types of background material, but a different approach would be needed for predicting mixed type glass contamination in refuse-derived fuel. 

  • 17.
    Zaccaria, Valentina
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Dik, Andreas
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Bitén, Nikolas
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Aslanidou, Ioanna
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Kyprianidis, Konstantinos
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Conceptual Design of a 3-Shaft Turbofan Engine with Reduced Fuel Consumption for 20252017Ingår i: Energy Procedia / [ed] Elsevier, 2017Konferensbidrag (Refereegranskat)
    Abstract [en]

    In the past decade, aircraft fuel burn has been continually decreased, mainly by improving thermal and propulsion efficiencies with consequent decrement in specific fuel consumption. In view of future emission specifications, the requirements for SFC in the forthcoming years are expected to become more stringent. In this paper, a preliminary design of a turbofan engine for entry in service in 2025 was performed. The design of a baseline 2010 EIS engine was improved according to 2025 specifications. A thermodynamic analysis was carried out to select optimal jet velocity ratio, pressure ratio, and temperatures with the goal of minimizing specific fuel consumption. A gas path layout was generated and an aerodynamic analysis was performed to optimize the engine stage by stage design. The optimization resulted in a 3-shaft turbofan jet engine with a 21% increase in fan diameter, a 2.2% increment in engine length, and a fuel burn improvement of 11% compared to the baseline engine, mainly due to an increment in propulsive efficiency. A sensitivity analysis was also conducted to highlight what the focus of technology development should be.

  • 18.
    Zaccaria, Valentina
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Rahman, Moksadur
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Aslanidou, Ioanna
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Kyprianidis, Konstantinos
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    A review of information fusion methodsfor gas turbine diagnostics2019Ingår i: Sustainability, ISSN 2071-1050, E-ISSN 2071-1050, Vol. 11, nr 22, artikel-id 6202Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    The correct and early detection of incipient faults or severe degradation phenomena in gas turbine systems is essential for safe and cost-effective operations. A multitude of monitoring and diagnostic systems were developed and tested in the last few decades. The current computational capability of modern digital systems was exploited for both accurate physics-based methods and artificial intelligence or machine learning methods. However, progress is rather limited and none of the methods explored so far seem to be superior to others. One solution to enhance diagnostic systems exploiting the advantages of various techniques is to fuse the information coming from different tools, for example, through statistical methods. Information fusion techniques such as Bayesian networks, fuzzy logic, or probabilistic neural networks can be used to implement a decision support system. This paper presents a comprehensive review of information and decision fusion methods applied to gas turbine diagnostics and the use of probabilistic reasoning to enhance diagnostic accuracy. The different solutions presented in the literature are compared, and major challenges for practical implementation on an industrial gas turbine are discussed. Detecting and isolating faults in a system is a complex problem with many uncertainties, including the integrity of available information. The capability of different information fusion techniques to deal with uncertainty are also compared and discussed. Based on the lessons learned, new perspectives for diagnostics and a decision support system are proposed. 

  • 19.
    Zaccaria, Valentina
    et al.
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Stenfelt, Mikael
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Aslanidou, Ioanna
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Kyprianidis, Konstantinos
    Mälardalens högskola, Akademin för ekonomi, samhälle och teknik, Framtidens energi.
    Fleet monitoring and diagnostics framework based on digital twin of aero-engines2018Ingår i: Proceedings of the ASME Turbo Expo, American Society of Mechanical Engineers (ASME) , 2018, Vol. 6Konferensbidrag (Refereegranskat)
    Abstract [en]

    Monitoring aircraft performance in a fleet is fundamental to ensure optimal operation and promptly detect anomalies that can increase fuel consumption or compromise flight safety. Accurate failure detection and life prediction methods also result in reduced maintenance costs. The major challenges in fleet monitoring are the great amount of collected data that need to be processed and the variability between engines of the fleet, which requires adaptive models. In this paper, a framework for monitoring, diagnostics, and health management of a fleet of aircrafts is proposed. The framework consists of a multi-level approach: starting from thresholds exceedance monitoring, problematic engines are isolated, on which a fault detection system is then applied. Different methods for fault isolation, identification, and quantification are presented and compared, and the related challenges and opportunities are discussed. This conceptual strategy is tested on fleet data generated through a performance model of a turbofan engine, considering engine-to-engine and flight-to-flight variations and uncertainties in sensor measurements. Limitations of physics-based methods and machine learning techniques are investigated and the needs for fleet diagnostics are highlighted. 

  • 20.
    Zachos, Pavlos K.
    et al.
    Cranfield University, United Kingdom.
    Aslanidou, Ioanna
    Cranfield University, United Kingdom.
    Pachidis, Vassilios
    Cranfield University, United Kingdom.
    Singh, Riti
    Cranfield University, United Kingdom.
    A sub-idle compressor characteristic generation method with enhanced physical background2011Ingår i: Journal of engineering for gas turbines and power, ISSN 0742-4795, E-ISSN 1528-8919, Vol. 133, nr 8Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Sub-idle is a very challenging operating region as the performance of a gas turbineengine changes significantly compared with design conditions. In addition, the regulationsfor new and existing engines are becoming stricter and the prediction of enginerelight capability is essential. In order to predict the performance of an engine, detailedcomponent maps are required. The data obtained from rig tests are insufficient at lowspeeds, creating the need for generation of maps within the sub-idle regime. The first steptoward this direction is the use of an extrapolation process. This is a purely mathematicalprocess and the results are not usually of sufficient accuracy. In addition, this methoddoes not provide any insight on the physical phenomena governing the operation of thecompressor at low speeds. The accuracy of the resulting compressor map can be increasedwith a better low speed region definition; this can be achieved via the thoroughstudy of a locked rotor compressor, enabling the derivation of the zero rotational speedline and allowing an interpolation process for the generation of the low speed part of thecharacteristic. In this work, an enhanced sub-idle compressor map generation techniqueis proposed. The suggested methodology enables the generation of characteristics at faroff-design conditions with enhanced physical background. Alternative parameters formap representation are also introduced. Provided that the all the blade rows of thecompressor are of known geometry, a numerical analysis is used for the calculation of thecharacteristic of the half stage and a stage stacking method is employed to create theentire compressor characteristic. This way, the sub-idle region of the map can be calculatedthrough interpolation, which provides a more accurate and predictive technique.Application of the method for compressor map generation showed that the proposedinterpolation approach is robust and capable of enhancing any performance simulationtool used for the prediction of transient altitude relight or ground-starting maneuvers.

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