Enhancing compressor distortion tolerance by asymmetric stator control

This paper describes a preliminary study of a method for increasing compressor tolerance in circumferential distortion through asymmetric vane stagger control. The changes in vane stagger about the circumference are used to increase compressor pressure rise and flow capability over part of the annulus and decrease these over the rest. The average pressure rise and flow thus remain roughly constant but the velocity distortion is reduced (and can even be made zero). Calculations are carried out to show the magnitude of the vane motions that must be used, and it is found that significant increases in distoriton attenuation can be achieved with realistic vane swings. In addition, the asymmetric vane stagger scheme leads to a substantial decrease in stall pressure rise loss due to inlet total pressure distortion. This type of control strategy appears worthy of further investigation, both theoretical and experimental.