The quest for greener, more efficient aircraft engines, along with the continuous growth of the aviation sector expected in the next decades, are the main drivers for the development of innovative aero-engine configurations to reduce CO2 and NOx emissions. To achieve such goal, new compression system technologies are currently being designed and investigated. These emerging components are characterized by atypical and complex flow fields, requiring to explore, since the early stages of the design process, a wide design space in quest of the highest efficiency regions. Thanks to their simplicity, reduced order loss models are a valuable preliminary design tool that can be easily parametrized to provide a deep survey of the design space. Nevertheless, they often rely on semi-empirical correlations, whose validity range is often too narrow or, in general, not matching with the flow conditions of interest for modern turbomachinery applications.

The present work focuses on the entropy generation mechanisms occurring in modern transonic axial compressors. In particular, it aims at defining a set of loss correlations capable of estimating the contribution and the span wise distribution of the various loss sources, which could readily be employed in the analysis and design process of state-of-art transonic axial compressors.

In part I, the main loss generation mechanisms are described, along with a survey of loss correlations commonly employed for their evaluation. In a second step, selected loss models are deeply investigated and updated through physically based considerations. The result is a set of correlations of enhanced generality and accuracy.

In part II, the accuracy of both original and updated models is assessed by validation over experimental and numerical multi-fidelity datasets. At such extent, a transonic low aspect ratio compressor is selected, which is representative of the last stage high pressure compressor for an ultra high overall pressure ratio aero-engine. A detailed description of the implementation methodology is reported for each loss model, providing a clear definition of the input parameters, the adopted conventions, and the main underlying assumptions. The comparison with CFD results shows a good capability of the developed tool in predicting the span-wise loss distribution, as well as flexibility and robustness toward the selected input parameters.


Transonic Axial Compressors Loss Correlations: Part II \u2014  Loss Models Validation

Division / Sponsor:
International Gas Turbine Institute (IGTI)

Paper Proceedings: https://asmedigitalcollection.asme.org/GT/GT2020/volume/84058

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