圆弧槽处理机匣对影响跨声速压气机叶根失速先兆发展过程的实验研究

Experimental Study on Hub Stall Instability Evolution in a Transonic Compressor with Arc-Shaped Slot Casing Treatment

针对在一台跨声速压气机上发现的叶根型失速先兆局部喘振,通过实验方法,探究了一种特殊设计的圆弧槽处理机匣对局部喘振型叶根失速先兆发展过程的影响。通过对比实壁机匣和圆弧槽处理机匣的实验数据,压气机的稳定工作裕度在应用处理机匣的情况下拓宽了19.88%,而总压比峰值点仅降低了0.3%,同时绝热效率基本保持不变。结果表明:(1)实壁机匣情况下,压气机失速时伴有低频的局部喘振和高频的失速团信号,而安装圆弧槽处理机匣的实验结果表明在同样的流量下局部喘振现象依然存在,但此时压气机仍能稳定工作,证明局部喘振的发生与叶根高负荷有关,但与叶尖的流动情况无关;(2)处理机匣的使用改善了叶尖流动情况,推迟了转子叶尖区域高频旋转失速团的发生,从而实现了对叶根型失速先兆压气机的拓稳效果,同时这也揭示了在局部喘振型失速发展过程中,由局部喘振诱导的高频、发生于叶尖的旋转失速团是压气机失速的重要原因。

Focusing on the hub-initiated stall inception partial surge in a transonic axial compressor,experimental investigations are carried out with a special designed arc-shaped slot casing treatment. With the comparison between solid casing and arc-shaped slot casing treatment,both the compressor performance and the instability evolution are analyzed. The stall margin is successfully enhanced by 19.88% with the specifically designed casing treatment,while the total pressure ratio only drops by 0.3% and the adiabatic efficiency does not quite change,which is compared with the original solid wall case. At the same time,there are two main findings：（1）With the solid casing,the compressor stalls with low-frequency partial surge and high-frequency stall cells.But the results of instability evolution with casing treatment present that partial surge still occurs at nearly the same mass flow rate as the stall point of the solid wall case,while the compressor is still on stable operation. It presents that the occurrence of partial surge is related to the hub region rather than the rotor tip region.（2）The formation of rotating stall cells in the rotor tip region is delayed by the casing treatment improving the tip flow situation,which can explain why the stall margin of this compressor is enhanced. Meanwhile,the formation of the high-frequency tip-initiated rotating stall cells induced by partial surge is necessary for substantial drop of the compressor performance in the hub stall evolution.