Experimental investigation of flow field in both straight and positive bowed stator passages with cantilever blades

Experimental investigation was performed in a double stages low speed axial compressor. The traverse flow field at the exit of second stator was measured in details at different working condition for both straight and positive bowed stator passages. The results show that the pressure diffusion ability in positive bowed stator passage is stronger than in straight stator at design condition and near stall condition but weaker in near maximum flow condition. There are two main vortexes in stator passage at design condition, which are up passage vortex and scraping vortex, respectively. The scraping vortex in straight stator passage distributes a large area but much smaller in positive bowed stator passage. The up passage vortex disappears in near chocking condition. However, the scraping vortex enhances in the straight stator passage while it changes a little in positive bowed stator passage. In near stall condition, the flow separation happens along the full span wise and all the vortexes disappear. Compared with the outflow angle, the ability of flow under-turning in positive bowed stator passage is weaker than in straight stator in whole mass flow work condition. However, the distribution of flow angle along the blade height is more uniform in positive bowed stator passage than in straight stator passage.