涡轮叶片尾缘气膜冷却耦合传热的数值模拟

Conjugate Heat Transfer Simulation of Film Cooling on Trailing Edge Cutback of Gas Turbine Blades

采用耦合方法对燃气轮机涡轮叶片尾缘气膜冷却流场进行数值模拟,并与绝热方法下的结果进行对比,得到不同吹风比和不同吸力面厚度下的气膜冷却规律。结果表明:与绝热方法相比,采用耦合方法时气膜冷却效率曲线更平缓,吸力面温度分布均匀,压力面尾部上方区域温度梯度较大;增大吹风比可以减弱吸力面导热对气膜冷却效率的影响,且能有效抑制流体与壁面的分离;随着吸力面厚度的增加,0.6~0.76等温度比线区域内流体温度发生变化,在劈缝出口下游温度升高,在下游的远距离处温度降低。

A conjugate heat transfer simulation was conducted on the film cooling flow field at the trailing edge of gas turbine blades,and the simulation results were compared with that of adiabatic method,thus finding the film cooling behavior at different blow ratios and suction surface thickness.Results show that compared with the adiabatic method,the curve of film cooling efficiency obtained by conjugate method is more gentle,with more uniform temperature distribution on the suction surface but a higher temperature gradient above the pressure surface.Increasing the blow ratio could reduce the effect of heat conduction on film cooling and inhibit the separation of the fluid from wall surface effectively.As the thickness of the suction surface increases,the fluid temperature in the area from 0.6 to 0.76 isotherm changes,the temperature rises in the downstream of cutback outlet and decreases in the place far from the cutback.