Effect of Rotating Inlet Distortion with Multi-distorted Regions on Compressor Stability

The influence of rotating inlet distortion (RID) on compressor stability has attracted widespread attention in academia, mainly about stall margin and onset of rotating stall. However, most of the experiments are conducted on low-speed compressors, most of the simulations are conducted on rotors, and only one distorted region exists at the inlet. This paper aims to explore the influence of RID with more than one distorted region on rotating stall development in the high-speed multi-row compressor. Flow instability of NASA stage 35 under uniform inlet condition and RID with different rotational speeds are simulated. Results indicate that, when rotating stall is fully developed, the RID has little influence on the rotational frequency and number of stall cells, which may be the inherent characteristics of the compressor. However, the onset and the initial state of rotating stall will be primarily influenced. RID with lower rotational speed will delay the occurrence of rotating stall, RID with higher rotational speed will exceed the occurrence of rotating stall but will experience two types of stall states. The causes for these flow phenomena are then discussed in detail. This research’s findings can help understand the instability behavior of downstream compressor in multi-spool engine, under the distortion flow induced by upstream compressor.