U型进气管道对某离心压气机性能的影响

采用实验和数值模拟的方法研究了U型管道进气对某离心压气机性能的影响.实验结果显示,相比直管进气,U型管道进气在大流量工况下显著降低了压气机性能,压比、效率的下降量分别可达10%和18%以上.数值分析表明:U型管道进气时,其出口产生静压和总压畸变;压气机下游蜗壳因几何周向不均而存在相应的压力畸变,该畸变沿叶轮槽道向上游传播的过程中与进气畸变发生耦合.这种耦合作用改变了叶轮进口的流场结构,使叶轮槽道流量分布发生变化,叶轮对应畸变区域的熵值增加;同时还改变了叶片表面静压的分布形式,使整个叶轮主叶片的平均载荷增大约8%. 

Influence of the U-shape inlet pipe on a centrifugal compressor performance

The effects of the U-shape pipe on a centrifugal compressor were investigated with experimental and numerical simulation methods. Compared with straight pipe inlet, the bend pipe resulted in a significant performance degradation of the compressor at the high mass flow rate. The pressure ratio and efficiency dropped by 10% and 18%, respectively. The numerical results show that the distortions of the static pressure and the total pressure were generated at the outlet of U-shape pipe. The pressure distortions were induced by the circumferential nonuniform geometry of downstream compressor volute. When transported to the upstream blade channels, the outlet pressure distortions encountered with the inlet pressure distortions. These coupled distortions changed the flow structure and inlet conditions in the impeller inlet, and also the mass flow rates distribution in the blade channels. The entropy increase existed at the distortion regions of the impeller. Meanwhile, the mean load of whole main blades increased about 8% due to the variations of the static pressure distribution at main blade surfaces.