局部喘振现象物理本质的研究

Study on Physical Mechanism of Partial Surge

局部喘振是在跨声速压气机发现的一种流动现象,其物理性质与喘振较为类似。针对局部喘振的物理本质的探索可以丰富跨声速压气机失稳理论,对于跨声速压气机扩稳有重要意义。本文针对这一问题,结合B参数模型,在跨声速压气机实验台上通过不同进气管道方案来改变实验装置对应的B参数,从时域、频域两方面对比研究不同B参数状态下的压气机的失稳过程,进一步分析不同B参数条件下失稳过程形态的演变规律。实验结果表明,B参数为0.39时,局部喘振现象并未发生,压气机直接进入喘振而失稳;B参数为0.51时,局部喘振诱发喘振而致使压气机失稳;而B参数为0.7时,局部喘振诱发旋转失速团导致压气机失稳。局部喘振现象既能诱发跨声速压气机发生旋转失速,也可以导致其直接进入喘振,因此局部喘振现象是一种失稳先兆。

Partial surge is a type of flow phenomena found in transonic axial compressor,which has similar characteristics as surge. To figure out the physical origin of partial surge could enrich transonic compressor instability theory,and it could be important to enlarge the mass flow range of transonic compressor. To solve this problem,based on Greitzer’s B parameter modal,experimental investigations are carried out. Inlet ducts with different length are mounted to change B factor of the system. Experimental data is analyzed by both time domain and frequency domain to analyze instability evolutions. The results indicate that： （1） as the B factor is 0.39,partial surge does not occur,while surge occurs in the end of the procedure. （2） As the B factor is 0.51,partial surge could lead into surge turning the compressor into instability. （3） As the B factor is 0.7, partial surge could lead into rotating stall cells at rotor tip region. Therefore,partial surge is a type of instability precursor,which could lead into not only rotating stall cells but also direct surge.