Experimental and numerical study on aerodynamic stability of compressor L-inlet duct

Abstract

Total pressure loss and vortex pair are the two independent flow phenomena that affect the flow quality at the compressor L-inlet duct (CLID). Both flow phenomena do affect the compressor efficiency, aerodynamic stability and surge margin. However, no general report on the control of the two flow phenomena is found in the open literature. Therefore, in this study, a wind tunnel test bench is independently built to undertake the optical diagnostic test research of the CLID internal flow. Then, the internal flow in CLID is investigated with both the Particle Image Velocimetry (PIV) test and the numerical simulation. Furthermore, the effects of typical parameters on the CLID aerodynamic stability are investigated. Finally, based on the parametric sensitivity analysis, an orthogonal design method with array L16(45) is adopted to achieve the optimized CLID aerodynamic design. Results show that the designed wind tunnel test bench can successfully carry out the PIV test, and the test error is controlled below 1.5%. PIV test results show that two counter rotating vortex pairs are generated at compressor inlet case annular section P-a4 (φ=180°) and P-a5 (φ=225°). They are believed to affect the compressor surge margin. SC60 is validated to capture the vortex pairs, DC60 is validated to capture the total pressure loss. The larger the width (a/D4), depth (b/D4) and cone diameter (D0/D4), the better the CLID aerodynamic stability. The optimized CLID aerodynamic design is achieved by the L16(45) orthogonal design.