Numerical Investigation Of Effects Of Boundary Layer Suction On The Performance Of Diffusion Cascade

Nowadays the axial compressor put a further demand on weight and dimension, lower weight and smaller dimension require higher single-stage load and pressure ratio. The control of boundary layer flow is the key factor to improve the compressor performance. The design of aspirated compressor indicates that the adoption of boundary layer suction technology can highly increase the compressor cascade loading and the capability of pressure diffusion, thus aspirated compressor is a new concept compressor with capacious advancement.The study object is an axial compressor with suction structure which concludes suction slot, suction cavum and suction pipe. The location of suction slot involve the suction side of stator and the hub near suction side of stator which with large turning angles. Based on the business software NUMECA, I made numerical study of the effects of suction location and suction flow rate on performance of low-speed compressor cascade. The study presents that boundary suction can on a certain extent reduce the influence of the horseshoe vortex and secondary flow on flows, can postpone the trend and reduce the intensity of flow separation, and can alleviate the accumulation of low energy fluid in the suction corner and abate the effect of flow choke, and therefore the flow loss is reduced and the diffusion is recovered.In this dissertation, the effects of various suction mode and suction flow rate on the flow field were analyzed detailed. The suction mode includes hub suction, suction side suction and compounding suction. The investigation indicates that with the same inlet Mach number, given a suction mode exists an optimal suction flow rate. All suction modes can reduce the total pressure loss, but single suction mode couldn't avoid flow separation, the compounding suction mode can control the 3D separation flow in stator cascade better and the total pressure loss reduced by 28.5%.At the end of this thesis is the analysis of flow in the aspirated cavum. The study indicates that the large-scale vortex in aspirated cavum can result in the increase of flow loss, to some extent it would reduce the benefit which induced by boundary suction...