Control mechanisms of endwall profiling and its comparison with bowed blading on flow field and performance of a highly-loaded compressor cascade

Abstract

In order to exploit the control mechanism of endwall profiling (EP) on flow field and performance of compressors, this paper carried out investigations on non-axisymmetric endwall profiling (NAEP), axisymmetric endwall profiling (AEP) and the comparison with bowed blading in a highly-loaded compressor cascade. Firstly, the influence mechanism of NAEP on corner separation and its design strategies were investigated. Pattern effect of NAEP, axial effect and height effect of concave/convex of NAEP were studied. Secondly, the influence mechanism of AEP on corner separation and its design strategies were studied. Thirdly, the comparison of flow mechanism between endwall profiling (EP) and bowed blading was carried out. Results show that although all the NAEP patterns can reduce the cross-passage pressure gradient, they exhibit distinct different control effects on corner separation. It is indicated that the radially inward pressure gradient, rather than the cross-passage pressure gradient near the endwall, is the key to control corner separations. The endwall cross-passage pressure gradient remained after AEP. However, the corner separation was also eliminated effectively by AEP with a concave curvature, with loss coefficient reduced by 20.07%. At last, compared with bowed blading, the cascade with EPs exhibits a higher overall performance but a lower control effect on corner separation.