尾缘形状对低压涡轮叶栅气动性能的影响

摘要

To reduce the energy loss of high-lift low pressure turbine ( LPT ) and improve the aerodynamic performance, numerical simulation method was used to study the effects of trailing edge shapes on the aerodynamic performance of high-lift LPT L2F cascades. The effects of three trailing edge shapes, deflected trailing edge, increasing trailing edge thickness and the Gurney flap on the energy loss and flow were studied. It is shown that the three trailing edge shapes all can increase flow turning angle, decrease energy loss coefficient at low Reynolds number ( Re) and increase the energy loss at high Re, however the deflected trailing edge is more effective than the others to improve the aerodynamic performance of the LPT cascades. Deflected trailing edge decrease energy loss by 16.5% at Re of 20000 and free-stream turbulence intensities ( FSTI ) of 3.3%. The three trailing edge shapes deflected the main flow, accelerate boundary layer flow on the suction side, and suppress the flow separation, which tend to decrease the energy loss. However the three trailing edge shapes enhance the mixing flow behind the trailing edge, which tend to increase the energy loss.%为减小高负荷低压涡轮叶型损失,提高低压涡轮叶栅气动性能,采用数值模拟方法研究尾缘形状对高负荷前加载低压涡轮叶栅L2F气动性能的影响.对比尾缘偏斜、增加尾缘厚度和Gurney襟翼对叶栅能量损失和流动的影响.结果表明:3种尾缘形状都能增加气流折转角,在低雷诺数时减小能量损失,在高雷诺数时增加损失,但总体上尾缘偏斜提高气动性能的效果更好.雷诺数为20000、湍流度为3%时,尾缘偏斜能够减小16.5%叶栅能量损失,增加3.3%气流折转角.3种尾缘形状都使主流发生偏转,加速了吸力面边界层流动,抑制了流动分离,有利于减小损失;但尾缘改型增强了尾缘后流动掺混,会增加损失.