NUMERICAL INVESTIGATION ON TANDEM COMPRESSOR CASCADES

Tandem blade arrangement of axial compressors has been proposed to obtain high loading and turning compared to a single blade. The objectives of the current study is to investigate the effect of percent pitch, axial overlap and incidence angle for a low speed axial compressor stator cascade and to supplement the results with the flow structures observed. 2-D numerical study was conducted using a finite volume scheme which solves the RANS equations along with the Spalart-Allmaras turbulence model. Comparison of flow structures corresponding to different percent pitch, axial overlap and incidence angle has been made to highlight all prominent flow mechanisms. It is observed that the flow through the gap nozzle between the two blades has significant effects on losses. The incidence range of the tandem cascades is found to be superior to the corresponding single blade cases.