Experimental investigations on the effects of bowed stator in a highly loaded axial compressor stage

Comparative studies of two stators in a highly loaded axial compressor stage were investigated experimentally in a Low-speed Large-scale Axial compressor test Facility. The two stators, one was designed with conventional radial stacking method called as Stator A, the other one was designed with positive dihedral near the two endwalls based on Stator A, i.e. bowed stator, called as Stator B, were assembled with the same rotor and IGV blades separately to constitute two 1.5 stages. During the experimental investigations, both the stage characteristics and detailed stator inlet/outlet flow fields were investigated with different rotor tip gap sizes (1.0% and 1.75% blade span). The results show that Stator B makes a redistribution of the low-energy fluid in blade spanwise and suppresses the growing of hub corner separation, which can reduce the endwall loss significantly and increase the stator blade loading and result a significant improvement of compressor performance. However, for different rotor tip gaps, because of the redistribution effect of the spanwise mass flow rate caused by the tip leakage flow blockage, the effects of the bowed stator on the performances of the investigated highly loaded compressor stage are changed accordingly.