A sub-idle compressor characteristic generation method with enhanced physical background
2011 (English)In: Journal of engineering for gas turbines and power, ISSN 0742-4795, E-ISSN 1528-8919, Vol. 133, no 8Article in journal (Refereed) Published
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.
Place, publisher, year, edition, pages
2011. Vol. 133, no 8
IdentifiersURN: urn:nbn:se:mdh:diva-33998DOI: 10.1115/1.4002820OAI: oai:DiVA.org:mdh-33998DiVA: diva2:1050282