Investigation on corner stall prediction and flow control by blended blade and end wall technology in a compressor cascade based on modified Spalart-Allmaras model

Corner stall has a significant impact on the performance of compressor cascades, but it is difficult to predict precisely using conventional Reynolds-averaged Navier-Stokes models. In view of this, first, the Spalart-Allmaras (SA) turbulence model modified with helicity is recalibrated to predict corner stall accurately. The internal reasons why the modified SA model does not overestimate the extent and intensity of corner stall as the original SA model is further explored through the analysis of turbulence transport nature. The investigation of corner stall control in a modified National Advisory Committee for Aeronautics 65 cascade by the blended blade and end wall (BBEW) technology is then carried out using the recalibrated MSA model. The numerical results indicate that the BBEW technology can eliminate the separation vortex on the end wall and change the flow field from corner stall to corner separation. The best BBEW scheme reduces the total pressure loss coefficient by 14.13%. The BBEW technology can most significantly enhance the aerodynamic performance of the compressor cascade when the maximum BBEW thickness is close to the trailing edge. When the maximum BBEW thickness is in the same position, the control effect rises first and subsequently falls as the maximum BBEW thickness grows. These research results serve as a guide for choosing turbulence models and designing the BBEW schemes.