Flow separation and vortex motion in flow filed of two stage axial compressor

To understand the detailed internal flow law of two stage compressor flow filed clearly, the detailed numerical simulation is carried out for the internal flow field of a two stage compressor of some multistage subsonic axial compressor. Simultaneously, the topology analysis theory is introduced, the flow separation and vortex development are qualitatively analyzed based on the vortex dynamics theory. The flow field analyses of the two-stage compressor at three different operating conditions show that, compared to the change of the separation range, the change of separation type plays a more important role on the compressor performance. When the flow approaches to the stall point, the separation range is continuously increased for the rotor cascade. While for the stator cascade, the separation range is increased, and in the mean time, the separation type is also changed. In a compressor cascade, the passage vortex intensity is weak and is not a primary role in the whole flow field characteristics, and the trailing vortex has a greater effect on compressor performance.