斜缝气膜冷却曲面模型的数值模拟

Numerical Simulation of Slot Film Cooling Model for Curved Surfaces

为研究燃气轮机叶片表面曲率对气膜冷却性能的影响,对二维斜缝曲面模型(凹面、凸面和平板)进行了数值模拟,选取冷却流体射流入射角35°、主射流密度比1.5,采用RNGk-ε湍流模型计算得到不同吹风比(0.5、1.2和2.0)下斜缝气膜冷却曲面模型壁面的传热系数.结果表明:低吹风比(M=0.5)时,壁面压力梯度越大,传热系数越小;中吹风比(M=1.2)时,射流对主流扰动加剧,传热加强,凹面总体传热系数比凸面小;高吹风比(M=2.0)时,曲率对传热系数的影响减弱,传热系数差异不大.

To study the effect of surface curvature on film cooling performance of turbine blade,a numerical simulation was carried out to the two-dimensional slot model for curved（concave,convex and plane） surfaces,during which heat-transfer coefficients on above surfaces were calculated at an injection angle of 35°,a density ratio of 1.5 and at different blowing ratios（0.5,1.2 and 2.0） using RNG k-ε turbulent model.Results show that at a low blowing ratio of 0.5,the heat-transfer coefficient reduces with rising pressure gradient on curved surfaces;at a medium blowing ratio of 1.2,the heat-transfer coefficient is intensified on all surfaces due to enhanced disturbance by injection flow,in which case,the heat transfer on convex surface is weaker than on concave surface;at a high blowing ratio of 2.0,the surface curvature effects little on heat transfer,resulting in basically the same heat-transfer coefficient on all surfaces.