涡轮导向器缘板安装缝隙泄漏特性数值模拟

针对某航空发动机涡轮导向器,采用数值模拟的方法研究了缘板安装缝隙泄漏流对叶栅通道流场结构及叶栅性能参数的影响,对比分析了不同泄漏流压力、缝隙宽度及缝隙相对位置条件下的泄漏量,及其对叶栅性能参数的影响规律.研究发现:在压差作用下冷气通过缘板安装缝隙进入燃气主流通道并在中段的位置形成螺旋涡系,对端壁二次流产生明显影响,其作用效果沿叶高方向逐渐降低,最大影响区域为44.44%叶高.计算结果表明:随着泄漏流压力的提高、缝隙宽度的增加、缝隙与发动机主轴方向夹角的变大,叶栅的能量损失系数和泄漏量都呈现出了单调增加的趋势.在研究的参数范围内,涡轮缘板安装缝隙导致的泄漏流可使叶栅的能量损失系数增加14%~62%. 

Numerical simulation of leakage characteristic of assembled endwall slot of turbine guide vane

Numerical simulations were applied to study the leakage flow of assembled endwall slot of turbine guide vane of an aero-engine. The effects of leakage flow on the structure of flow field of cascade passage and performance parameters of the cascade were also discussed. The leakage flow pressures, the slot width and position of the slot were changed to investigate the rules of leakage flow rate and energy loss coefficient varying with these parameters and discover the effect rules. It is found that the leakage can appear due to different pressures between cooling air and gas, spiral vortex system is formed in the middle position of the slot at the same time, and the leakage flow affects the secondary flow around the endwall significantly. The effect decreases along the direction of blade height and the largest region is up to 44.44% of the blade height. With the increase of leakage flow pressure, the slot width and the angle between the slot and major axis of engine, the energy loss coefficient of the cascade and the leakage flow rate increase monotonically. Numerical results show that the energy loss coefficient of the cascade increases by 14%-62% because of the leakage flow through the slot of the endwall in the parameter range of present study.