高转速自由盘流动换热相似性数值研究

Numerical Study on the Similarity of Flow and Heat Transfer on a High-Speed Rotating Free Disk

高速旋转盘腔中作功引起气流风阻温升显著,气流与盘面的换热量不仅取决于换热系数,还取决于气流温度。本文针对高转速自由盘模型,采用数值方法对影响盘面换热系数相似性的无量纲数和影响气流温度场相似性的无量纲数进行了研究。分别在发动机工况以及采用不同相似准则得到的实验工况下,进行了自由盘流动换热数值模拟,得到了旋转雷诺数和旋转马赫数对换热系数和气流温度相似性的影响。计算结果显示:仅需保证发动机状态与实验状态的旋转雷诺数相等就可保证局部努塞尔数相同;仅需保证发动机状态与实验状态的旋转马赫数相等就可保证绝热壁温分布相同;但只有保证实验状态和发动机状态的旋转雷诺数和旋转马赫数都相等时,无量纲换热量才保持一致。

In high-speed rotor-stator cavity,the temperature rise of the airflow produced by the rotor work is remarkable.The heat flux exchanged between the airflow and the disk surface depends not only on the convective heat transfer coefficient but also on the airflow temperature.In this paper,for a highspeed rotating free disk model,numerical method was used to study the dimensionless numbers that affect the similarity of the convective heat transfer coefficient and the airflow temperature.These numerical simulations were carried out under the engine typical operating conditions(high temperature)and experimental conditions(low temperature)with different rotating Reynolds number and rotating Mach number.The numerical results suggest that the local Nusselt number at experimental conditions equals to that of engine condition is only caused by same rotating Reynolds number;the adiabatic-disc temperature at experimental conditions equals to that of engine condition is only caused by same rotating Mach number.When the rotating Reynolds number and the rotating Mach number are the same,the dimensionless heat flux at the experimental conditions equals to that of the engine condition.