间隙变化对轴流压气机转子近失速工况叶顶流场的影响研究

为研究间隙变化对轴流压气机转子近失速工况下叶顶流场结构的影响，以轴流压气机转子Rotor37为研究对象，对其叶顶流场进行定常和非定常的数值模拟。计算结果表明：随着叶顶间隙的减小，压气机的总压比和等熵效率均有所提高，稳定运行范围扩大；2倍设计间隙下，叶尖泄漏涡经激波作用后发生膨胀破碎，堵塞来流通道，诱发压气机堵塞失速；0.5倍设计间隙下，吸力面流动分离加剧，发生回流，部分回流与来流在压力面前缘上游发生干涉，进口堵塞加剧，致使部分来流从前缘溢出，导致压气机叶尖失速；不同间隙下压气机失速过程的主导因素不同，大间隙下失速由叶尖泄漏涡破碎的非定常波动引起，小间隙下失速主要由流动分离引发的周期性前缘溢流所主导。

Study of the effect of clearance variation on flow field at the top of blade of an axial compressor rotor under near stall condition

In order to further understand the influence of clearance variation on the flow field structure of the top of blade of an axial compressor rotor under the near stall condition, the axial compressor rotor Rotor37 was taken as the object of study, and its flow field at the top of blade was numerically simulated in both steady and unsteady forms. The calculation results show that with the reduction of the clearance at the top of blade, the total pressure ratio and isentropic efficiency of the compressor are improved, and the stable operation range is enlarged; under 2 times of the design clearance, the tip leakage vortex is expanded and broken by the action of excitation wave, which blocks the inlet flow channel and induces the compressor to clog and stall; under half of the design clearance, the flow separation of the suction surface is intensified, backflow occurs, part of the backflow interferes with the incoming flow upstream of the front edge of the pressure surface front, and the inlet blockage is intensified, resulting in part of the incoming flow overflowing from the front edge, inducing the compressor tip stall; the dominant factors of the stall process of the compressor with different clearances are different, the stall under the large clearance is caused by the unsteady fluctuation of the tip leakage vortex crushing, while the stall under the small clearance is mainly dominated by the cyclic leading edge overflowing induced by the flow separation.