吸雨对压气机叶栅气动性能影响的实验研究

Experimental Research of Water Ingestion on Aerodynamic Performance of Compressor Cascade

针对雨水会导致飞机发动机非正常运行的实际问题,以压气机静叶叶栅为对象开展了压气机吸雨实验,探究了0.5马赫数和同一进口总压条件下不同来流含水量对压气机气动性能的影响。实验结果表明:来流水滴在压气机叶栅中会发生充分破碎,不同含水量来流破碎后水滴粒径基本一致,极限水滴破碎粒径约为13.3μm。随来流含水量增加,叶栅压力面静压基本不变,吸力面静压升高,因此叶片载荷系数降低。同时,总压损失系数随含水量增大而增大,当含水量为6.41%时,相对于干空气流动,总压损失系数大致上增加了一倍。另外,来流含水量对叶栅落后角和气流转折角的影响主要体现在叶栅的尾缘附近,其中压力面侧壁附近角度变化为1°~3°。由实验结果推测雨水影响压气机叶栅气动性能的机理为:雨水进入叶栅中发生充分破碎,消耗主流部分动能,使得来流总压沿着流动方向不断降低,来流含水量越大总压降低越多;破碎后水滴沉积在叶栅表面,在主流剪切力、壁面摩擦力和水膜表面张力共同作用下形成溪流流动,引起表面静压变化。

In terms of the off-design operation of aircraft engine with water ingestion,an experimental research was performed on a stator cascade of the compressor. The effects of different incoming water content on the aerodynamic performance were investigated under 0.5 Mach number and the same inlet total pressure. The experimental results show that the water droplets will be fully broken in the compressor cascade. The particle size of the water droplets is nearly the same after being broken under different water content,and the limit droplet breaking particle size is about 13.3μm. With the increase of the incoming water content,the static pressure on the pressure surface of the cascade is basically unchanged,while the static pressure on the suction surface increases,therefore,the loading coefficient of the cascade decreases. Also,the total pressure loss coefficient increases with the increase of water content. When the water content is 6.41%,the total pressure loss coefficient almost doubled compared with dry air flow. In addition,the influence of inlet water content on cascade deviation angle and flow turning angle is mainly reflected near the trailing edge of cascade,and the angle variation range of pressure side wall is 1° to 3°. According to the experimental results,it is speculated that the influence of water ingestion on the aerodynamic performance of the compressor cascades is as follows:On the one hand,rainwater is fully broken into the cascades and consumes part of the kinetic energy of the main flow,so that the total pressure of incoming flow decreases continuously along the flow direction. And the larger water ingestion mass flow leads to more total pressure loss. On the other hand,broken droplets will deposit on the cascade surface,forming a stream flow under the joint action of mainstream shear force,wall friction force and water film surface tension,causing surface static pressure changes.