Performance Limits of Axial Compressor Stages

Abstract

This paper presents a framework for estimating the upper limit of compressor stage efficiency. Using a compressor stage model with a representative design velocity distribution with turbulent boundary layers, losses are calculated as the sum of selected local irreversibilities, rather than from correlations based on data from existing machines. By considering only losses that cannot be eliminated and optimizing stage design variables for minimum loss, an upper bound on stage efficiency can be determined as a function of a small number of stage design parameters. The impact of the stage analysis results are evaluated in the context of gas turbine cycle performance. The implication from the results of the stage level and cycle analyses is that compressor efficiency improvements that result in substantial increases in cycle thermal efficiency are still to be realized.