攻角对端壁缝隙泄漏流气膜冷却的影响

Turbine Endwall Film Cooling With Combustor-Turbine Interface Gap Leakage Flow:Effect of Incidence Angle

本文中的实验在高压涡轮进口导叶平面叶栅中完成,叶栅端壁前缘开有模拟燃烧室涡轮连接处的缝隙。实验中采用GE-E^3高压涡轮进口导叶作为研究对象,缝隙与端壁表面夹角为30°。进口雷诺数(基于叶片轴向弦长和进口气流速度)为3.5×10~5,进口马赫数为0.1,泄漏流流量比为0.5%和2.0%。气膜有效度通过压力敏感漆(Pressure Sensitive Paint,PSP)进行测量。实验结果表明随泄漏流流量比的增加,端壁表面的平均气膜有效度有所增加;当来流攻角从i=+10°变化至i=-10°时,叶片前缘吸力面附近的端壁气膜有效度降低,但在整个端壁表面气膜有效度对攻角变化并不敏感。

The influence of incidence angle on film cooling effectiveness is studied on first-stage vane endwall with combustor-turbine interface slot. A baseline slot configuration is tested in a low speed four-blade cascade consisting of large scale model of the GE-E3 Nozzle Guide Vane （NGV）. The slot has a forward expansion angle of 30° to the endwall surface. The Reynolds number based on the axial chord and inlet velocity of the free-stream flow is 3.5×10^5, and the testing is done in a four-blade cascade with low Mach number condition （0.1 at the inlet） while the mass flow ratio of the coolant through the interface gap varies from 0.5% to 2.0%. The film-cooling effectiveness distributions are obtained using the PSP （pressure sensitive paint） technique. The results show that with blowing ratio increasing, the film cooling effectiveness increases on the endwall. As the incidence angle varies from i=＋10°to i=-10°, at low blowing ratio the film cooling effectiveness decreases near the leading edge suction side. As for the main passage endwall, with the incidence angle changing form i = ＋10° to i = -10° the averaged film cooling effectiveness changes slightly, while this trend will be eliminated by increasing the blowing ratio.