叶型几何设计弱化叶片外表面换热的作用

Effects of Airfoil Geometric Design to Reduce Blade External Heat Transfer

本文采用γ-Re_θ湍流转捩模型,数值模拟了两组不同叶型的涡轮叶栅表面的表面换热系数。结果证明:1)数值计算正确地预测了转捩发生位置,保证了表面换热系数模拟的可靠性;2)由于叶片型线的差异,叶片表面流动的转捩位置也不同。控制叶片表面边界层流动状态,推迟流动转捩,能够降低叶片热负荷。在相同进、出口气流条件下,选择不同的叶栅造型参数,可以调整所产生的涡轮叶型,从而增强或弱化叶片表面的换热。

Numerical simulation was used to predict surface heat transfer coefficients on two types of turbine cascade with SST and γ-R_(eθ) turbulent transition models.Results show that:1) the flow's transition is located correctly in numerical prediction,which ensures the credibility of predicting the surface heat transfer coefficients;2) Because of the different airfoil profiles,flow transition occurs at different locations.When the flow's boundary layer is controlled to delay its transition,the blade external heat flux can be reduced.At the same mflow conditions,various cascade parameters are chosen to generate different turbine blade samples,among which enhanced or weakened surface heat transfer are observed.