斜缝气膜冷却曲面模型的数值模拟

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.

Numerical Simulation of Slot Film Cooling Model for Curved Surfaces

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.