薄膜冷却射流的水模拟显示

本文通过水模拟实验,对涡轮叶片气膜冷却时射流的流场进行了研究。实验是在不同的攻角和不同的密流比下进行的。实验结果表明,当攻角一定时,密流比增加到某一数值后,薄膜不再是稳定的而是变成一群“旋涡串”。这种“旋涡串”的出现将大大削弱薄膜冷却的保护作用,故在设计时应竭力避免。本文还对“旋涡串”的出现机理作了初步分析,并根据实验结果提出了相应的经验公式。

The Visualization of Film Cooling Jets by Water Simulation

The flow field of film-cooled turbine vane is investigated in this paper with the help of water simulation.The experiments are carried out with different incident angles and blowing ratios.The results obtained from the experiments show that instead of stable film over the vane surface the film is changed into a series of vortices when the blowing ratio is increased beyond a certain value with the incident angles of the main stream being kept constant.As the occurrence of such vortices will greatly decrease the film cooling effectiveness,care should be taken to avoid such cases in design.The mechanism of its occurrence is discussed preliminarily and an empirical formula correlated to the experimental results is also presented in this paper for design references.