Full-annulus numerical investigation of influence on flow-field in an axial flow compressor with inlet distortion

Effects of inlet distortion on the performance and flow-field of subsonic axial-flow compressor were investigated with full-annulus numerical method. The inlet distortion was made by setting some barriers in the inlet radial passage. The unsteady numerical calculative results show that inlet distortion decreases the performance of the compression rotor and reduces stall margin by 3.1%. The fundamental flow mechanism was obtained by detailed analyzing the flow-filed in inlet extended passage and in rotor passage. The underlying mechanism is that there are some regions of low value of inlet flow angle on the ring surface of rotor inlet upstream and those make the separated location of boundary in some tip blade suction move toward blade leading, which leads to serious blockage in tip blade passage. The blockage makes the tip clearance leakage flow spill to adjacent tip passage at leading edge on higher blade span, inducing rotor stall consequently. When the inlet flow-field of rotor is uniform, the blockage caused by tip clearance leakage flow is the primary cause resulting in rotor stall.