Investigation of vortex structure and flow loss in a high-speed compressor cascade

In order to find out the internal flow characteristics of compressor cascade in high subsonic flow, research on the occurrence and development of high-speed compressor cascade vortex structures and flow loss are established. Firstly, the simulation model is erected and verified with experimental results; secondly, the main vortex structures, topological patterns and vortex models in the cascade passage are researched in detail; in the end, the relationship between flow loss and vortex structures is analyzed. Seven main vortex structures including horseshoe vortex, endwall span vortex, passage vortex, corner vortex, wall vortex, concentrated shedding vortex and trailing edge shedding vortex are observed in high-speed compressor cascade passage, and passage vortex which originates from the inlet endwall boundary layer is the main reason for the complicated vortex structures. As the angle of attack increases from 0° to 4°, although passage vortex vortex core separates earlier from the corner boundary layer, influences of passage vortex on the passage flow are weakened and concentrated shedding vortex at the trailing edge disappears. According to the cascade topological structure, with the disappearance of concentrated shedding vortex, spiral point corresponding to concentrated shedding vortex on suction surface disappears and the attachment line and separation line at trailing edge corresponding to midspan trailing edge shedding vortex are vanished, indicating that trailing edge shedding vortex only exists near endwall. According to the variance law of totalpressure loss coefficient in streamwise and spanwise direction, cascade passage flow loss is mainly attributed to strong sheering action caused by the complicated corner vortex structures, and the totalpressure loss near endwall is closely related to the occurrence and development of the main corner vortex structures; with the increase of angle of attack from 0° to 4°, however, influences of corner vortex structures are weakened, and the gap between totalpressure loss near endwall and midspan are narrowed as a result of the decrease of flow loss near endwall.