| Increasing the loading of compressors is one of the key methods to improve the thrust-weight ratio of aeroengine. However, the flow in modern compressors with high adverse pressure gradient is very complex and inclined to separate, especially in the hub-corner region formed by the blade suction surface and the hub end wall in rotors. Because of the restrict of performance improvement on transonic rotor produced by flow separation, boundary layer suction has become one of effective control method to attenuate separation, enlarge the working range of compressor and stabilize passage shock structure.The numerical simulation has been carried out on Rotor 67 to explore the mechanism of flow separation in corner region near hub and blade suction surface. In order to optimize the boundary layer suction in a transonic rotor, the effects of different boundary layer suction schemes on separation structure, static pressure distribution on blade surface, detached vortex at trailing edge and passage shock in tip region are all investigated. This research work can be summarized as follows:1. The flowfields of transonic rotor 67 at design and off-design conditions are both analyzed to explore internal separation mechanism and the variation of passage shock structure. The inducers of corner separation and suction surface separation are all investigated.2. Based on features of corner separation structure, several end-wall boundary layer suction slots are assigned to improve the flow characteristic of corner. In order to obtain the effective control method of boundary layer suction in the transonic rotor, the investigation of suction massflow rate and suction slot arrangement are both conducted.3. The analysis of suction surface separation is performed. In consideration of the effect of shock-boundary layer interaction on suction surface, some boundary layer suction positions are chosen to attenuate suction surface separation and improve the efficiency in blade tip region. |
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