透平级小翼-凹槽叶顶耦合传热性能研究

Investigations of Conjugate Heat Transfer on Winglet-Squealer Tip of a Turbine Stage

采用耦合传热方法研究了透平级小翼-凹槽叶顶的冷却传热性能,分析了耦合传热对两种凹槽叶顶(传统凹槽叶顶和带压力侧小翼凹槽叶顶)和动叶表面的传热系数、净热量减小量和气膜冷却效率分布的影响。结果表明:耦合传热对凹槽叶顶和动叶表面的冷却传热性能有显著影响。与纯流动区域计算结果相比:考虑耦合传热时传统凹槽叶顶面积平均传热系数增大了6.26%、带压力侧小翼凹槽叶顶面积平均传热系数减小了1.67%;考虑耦合传热时带压力侧小翼凹槽叶顶的动叶压力面平均传热系数增大了23.73%、吸力面平均传热系数增大了2.18%。叶顶结构对叶片表面的冷却传热性能影响较小。

Film cooling effect and heat transfer performance on the winglet-squealer tip of a turbine stage were investigated using the conjugate heat transfer method. The effects of conjugate heat transfer on heat transfer coefficient, net heat flux reduction, and film cooling effectiveness distributions on two types of squealer tip(i.e. conventional squealer tip and pressure-side winglet squealer tip) and rotor blade surfaces were analyzed. Compared to the single-fluid-domain computations, the area-averaged heat transfer coefficient on the conventional squealer tip is decreased by 6.26% and the area-averaged heat transfer coefficient on the pressure side winglet squealer tip is increased by 1.67%if the conjugate heat transfer in blade solid is considered. The area-averaged heat transfer coefficient on the pressure side surface of rotor blade with pressure-side winglet squealer tip is increased by23.73%, and area-averaged heat transfer coefficient on the suction side surface of rotor blade with pressure-side winglet squealer tip is increased by 2.18% if the conjugate heat transfer in blade solid is considered. However, the tip geometry has slight influence on the blade surface film cooling and heat transfer performance.