带孔式机匣处理的某工业压缩机稳态与瞬态特性实验

Experimental Investigation of Holed-Casing Treatment on Steady and Transient Characteristics in an Industrial Centrifugal Compressor

将孔式机匣处理方式应用于某工业离心压缩机,并对其特性进行了一系列定常和非定常实验研究.在机匣处理孔的两端,叶顶37%弦长位置和无叶扩压器内布置了动态压力传感器,在压缩机的稳定和喘振工况点进行了动态压力测试.实验结果发现,相比于实壁机匣,采用机匣处理方式后压缩机的喘振裕度约增加了10%且整机效率基本无下降.以机匣孔两端脉动压力的变化量作为指标,用于评估机匣孔内的流动方向.在近喘振点,脉动压力突然增加,此时发生的是抽吸流动.在近堵塞点,脉动压力的突变意味着旁通流动的发生.对动压信号进行信号分析发现,该实壁机匣和处理机匣压缩机在喘振前发生的都是模态失速而非脉冲失速.相比于实壁机匣,引入处理机匣后模态先兆波由于叶顶和机匣孔的相互作用得到了延迟,其失速团传播速度略高于实壁机匣的传播速度.

A new method of holed casing treatment was put forward and applied to an industrial centrifugalcompressor. A series of experimental investigations were conducted to study the ettects oi casing treatment on steady and transient performance of the compressor. Dynamic pressure is monitored under stable oper-ating point and surge occurrence condition at the following positions： two ends of the treated holes, 37% chord impeller tip position and the vaneless diffuser. By use of the casing treatment, the surge margin ofthe compressor is increased by about lO%Qd with negligible decrease in efficiency. Pulsating pressure change is taken as an indicator for evaluating the flow direction in the hole. Near surge point, when the static pressure of the bleeding port is larger than the turning point, a sudden increase in pulsating pressure indicates that the bleeding flow occurs. Near choke side, when the static pressure of the turning point is larger than the bleeding port, a severe change in pulsating pressure indicates that the bypass flow occurs. The signal analysis of the dynamic pressure at surge occurrence shows that the compressor stalls with a modal inception rather than a spike wave no matter casing treatment is applied or not. The travelling speedo{ the stall cell found in the compressor with casing treatment is faster than that with solid casing. The occurrence of modal precursor wave is delayed with casing treatment.