局部喘振的发生机理

为了深入研究高负荷压气机的失稳机制,明确失稳先兆局部喘振现象的发生机理,总结了某跨声压气机在均匀进气不同工作转速下失稳过程的实验结果,继而对其在进气畸变条件的失稳过程开展实验和数值研究.结果发现:在均匀进气条件下,局部喘振在低转速时并未发生,而发生于高转速情况下,推断局部喘振的发生与压气机叶根区域的相对高负荷有关.随后在高转速下降低叶根负荷,则局部喘振现象不再发生;而在低转速下升高叶根负荷,则局部喘振现象发生.所以得出结论,压气机叶根相对高负荷确实为局部喘振的发生条件.对于所研究的压气机,如果近失速点叶根扩散因子超过0.6,则会发生局部喘振现象. 

Occurrence mechanism of partial surge

To fully understand the instability mechanism of highly load compressors, the occurrence mechanism of instability inception partial surge was studied in detail. Based on the experimental data of instability evolution at different rotation speeds and uniform intake of a transonic compressor, the instability evolution under inlet distortion was studied by experimental and numerical methods. The results show that under uniform intake, partial surge can only be detected at high rotation speed while at low rotation speed partial surge can''t be detected. So it can be supposed that high blade loading at hub is related to the occurrence of partial surge. The results under different inlet condition suggest that lower blade loading in the hub region could prevent the occurrence of partial surge at high rotation speed while partial surge would occur at the low rotation speed if the blade loading in the hub region is higher. High blade loading in the hub is proved as a necessary condition for the occurrence of partial surge. In this compressor, if the diffusion factor exceeds 0.6 at near stall point, partial surge may occur.