进口畸变对轴流压气机流场影响的全通道数值研究

Full-Annulus Numerical Investigation of Influence on Flow-Field in an Axial Flow Compressor with Inlet Distortion

采用全通道非定常数值模拟方法研究了进口畸变对亚声速轴流压气机性能及流场的影响,数值模拟中通过在进口径向段设置栏杆的方式产生畸变,非定常数值计算结果表明进口总压畸变后降低了压气机转子的性能,失速裕度减小了3.1%。通过详细地分析压气机进口延伸段及内部流场表明,畸变后在转子上游进口环面上出现低值进气角区,促使部分通道叶顶吸力面附面层分离起始位置靠前,造成通道内堵塞严重,并使叶顶间隙泄漏流在更高叶展前缘处溢流到相邻叶片通道进而诱发转子失速,进口均匀时压气机失速主要是由叶顶间隙泄漏流引起的堵塞造成。

Effects of inlet distortion on the performance and flow-field of subsonic axial-flow compressor were investigated with full-annulus numerical method. The inlet distortion was made by setting some harriers in the inlet radial passage. The unsteady numerical calculative results show that inlet distortion decreases the performance of the compression rotor and reduces stall margin by 3.1%. The fundamental flow mecha- nism was obtained by detailed analyzing the flow-filed in inlet extended passage and in rotor passage. The underlying mechanism is that there are some regions of low value of inlet flow angle on the ring surface of ro- tor inlet upstream and those make the separated location of boundary in some tip blade suction move toward blade leading, which leads to serious blockage in tip blade passage. The blockage makes the tip clearance leakage flow spill to adjacent tip passage at leading edge on higher blade span, inducing rotor stall conse- quently. When the inlet flow-field of rotor is uniform, the blockage caused by tip clearance leakage flow is the primary cause resulting in rotor stall.