The structures of flow and vortices, especiallyt separated flow, on and near the blade surfaces of an annular compressor cascade under different incidences have been studied based on the oil-film images obtained in an experiment. The structures of the separated flow on the blade surfaces have been given. The results indicate that there are three different separation regions, namely, the top, middle and low separation region, in the annular compressor cascade. The low region is the largest and most important one. The top one is very small. The vortices near the blade tail may concentrate, intensify and even drop off with the increase of the incidence.
The structures of separated flow, especially, vortices, inside an annular compressor cascade at large incidences have been studied baized on the flow visualization images obtained by means of Laser-sheet method and 7-hole probe measurement. Combining with the flow structures on the blade surfaces obtained in part 1, the three-dimensional separation flow and vortex structure has been discussed and given. These results will be very helpful for the further development of a more accuracy physical model of the separated flow in compressors.
