粗糙度对多级压气机性能影响的数值模拟研究

Numerical Simulation of Effects of Roughness on Performance of Multistage Compressor

为了研究粗糙度对多级压气机气动特性的影响,采用三维数值模拟软件CFX,对3.5级压气机进行了研究。结果表明,相比于端壁粗糙度,叶片表面粗糙度对压气机性能影响更大;不同转速下,叶片表面粗糙度的增大会造成压气机压比和效率的降低,并且粗糙度增大越快,性能衰退也越快,其中设计转速下粗糙度对压气机的性能影响更大,当叶片表面粗糙度达到50μm时,峰值效率下降了5.25%,对应压比下降了1.33%。前面级叶片表面粗糙度加剧了后面级角区分离和尾迹损失,在压气机性能下降中所占比重更大;而最后一级粗糙度对分离区的影响很小,主要是增加了尾迹掺混造成的损失。单级粗糙度对压气机稳定工作区间影响很小,而全部级粗糙度增大了压气机的稳定工作区间,这是由于粗糙度造成的近失速点处的流量下降相比于堵塞流量的下降程度更大。

In order to investigate the effects of wall roughness on multistage compressor performance,three-dimension simulation software CFX was used to conduct preliminary research on the roughness of the blade and the end-wall respectively,as well as different quantity roughness of the blade surface.The results show that blade roughness has much more influence on performance than end-wall roughness.At different rotating speeds,the total pressure and isentropic efficiency usually decrease with increasing roughness,the faster the roughness increases,the faster the performance degradation will be.The roughness at the design speed has a greater influence on the compressor performance,when blade surface roughness increases to 50μm,the peak efficiency of the compressor decreases by 5.25%,the pressure ratio at the corresponding point decreases by 1.33%.The roughness of the former stage deteriorates the separation of the latter corners and the loss of the trails,which accounts for a larger proportion of the performance degradation of the compressor.The last-stage blade roughness has little effect on the separation zone,mainly due to the increase of the wake blending loss.Single-stage roughness has little effect on the compressor margin,while all-stage roughness increases the compressor margin,which is due to the fact that the flow drop caused by roughness at the near-stall point is greater than the blocking flow.