U型槽对高负荷低压涡轮叶型攻角特性影响

以某高负荷低压涡轮叶型为研究对象,分析了该叶型在低雷诺数下的攻角特性,并应用了表面嵌壁式U形槽的被动控制方法来提高该叶型的攻角裕度.数值模拟的结果表明:相比较大的正攻角流动状况,叶型较大的负攻角并不会引起吸力面大的流动分离,从而减小了叶型损失;表面嵌壁式U型槽通过推迟分离、加速再附来减小分离泡甚至减小湍流湿面积,从而降低叶型损失;表面嵌壁式U型槽能否提高该叶型的攻角裕度与开槽位置和深度有关系,在±15°攻角范围内72%轴向弦长位置处开槽明显的降低了叶型损失而开槽深度为0.40mm时叶型损失最小. 

Effect of U-grooves on high-lift low pressure turbine profile's incidence characteristics

The high-lift low pressure turbine blade profile incidence characteristics under low Reynolds number were investigated.The modification used recessed U-grooves to improve the profiles’ incidence margin.The numerical simulations suggest that compared with high incidence flow condition,lower incidence does not induce large separation which appears on the suction surface of the profile and hence lessens profile loss.The recessed U-grooves delay the separation location,accelerate reattach location,decrease the turbulent wetted area,thereby the separation bubble is suppressed and the profile loss decreases.Whether or not the recessed U-grooves can improve the incidence margin is related to the depth and location of the U-grooves.With±15 incidence degrees,the U-grooves located in 72% axial chord length showed lower profile loss,and when the depth was 0.40mm the profile loss was the lowest.