Transonic Multistage Axial Flow Compressor Off-design Performance Prediction

An improved streamline curvature numerical method is modified and applied to better approximate the flow fields of multi-stage transonic axial compressors. Total pressure loss and deviation correlations from a member of open literatures are compared and assessed to provide accurate and robust off-design stage performance through application to two two-stage transonic axial compressor examples. The optimum selection of loss and deviation correlations that would give the better prediction is obtained, and improvements in total pressure loss modeling and deviation modeling are implemented to ensure accurate and reliable transonic axial compressor off-design performance prediction. Especially, the new shock loss model, which accounts for shock geometry changes from near-choke to near-stall conditions, is presented. Shock loss is estimated as a function of inlet relative Mach number, blade section loading, solidity, leading edge radius, and suction surface profile. The effects on the tip secondary flow and the analysis of the loss in the transonic are also accounted in this paper. Finally, a stage-by-stage dynamic compression system model for predicting aerodynamic stability in multi-stage axial compressors is also given. Based on dynamic static pressure variations, a method of recognition of predicting aerodynamic stability is developed. Dada from two two-stage transonic axial compressors provides the basis for experimental comparisons. Overall and spanwise comparisons demonstrate the improved loss and deviation model give reasonable performance trends and general accurate results, indicating that physical understanding of the blade effects and the flow physics that underlie the new shock loss model improvements are correct and realistic. The comparisons of the surge margins also show that the stage-by-stage dynamic compression system model is capable of predicting the flow instability and give the reliable the results. In general, the effects of important flow phenomena relative to off-design performance of the compressor are adequately captured. These effects include shock loss, secondary flow,...