旋转状态下曲率对气膜与主流掺混区域的影响

气膜冷却是应用于航空燃气轮机上的冷却技术,旋转及表面曲率是影响气膜与 主流掺混区域的重要因素,通过数值计算方法对旋转状态下曲率对气膜与主流掺混区域的影 响进行了研究,湍流模型选取了k-ω模型.增加旋转速度,会引起吸力面气膜的分离; 固定转速,降低表面曲率半径,压力面气膜发生分离,吸力面气膜冷却效果得到改善.当动 量流量比在小于1的范围内变化时,旋转只改变压力面气膜与主流掺混区域的分布,而对吸 力面没有影响.

Curvature effects on the film cooling with the rotation

A computational heat transfer analysis was carried out to comprehend t he mechanism of rotation and the curvature effect on the film cooling which is i mportant in understanding the mixing process between the film coolant and the ho t stream air over the high pressure turbine blades. The CFX code was used to inv estigate the mixing effects of the rotation and the curvature. Turbulence model is k-ω model which has received wide application in the case of rotation. It was found that both rotation and curvature could affect the distribution of the fil m cooling. Rotation could lead to the departure of the film flow from the wall. The cooling effect will be improved on the suction side as the curvature str ength decreases. But on the pressure side, the departure of the film flow could be found. With the coolant-to-mainstream momentum flux ratio increased under u ni ty, the film trajectory on the pressure side will bend towards the blade tip. Bu t on the suction side, there is no clear influence.