缝槽平板振动气膜冷却数值仿真研究

Numerical Simulation of Film Cooling on Vibrating Slot Plate

关键词:  缝槽平板振动  绝热壁面有效温比  RANS仿真分析  DES仿真分析  气膜冷却

Key words:  Slot plat vibration  Adiabatic film effectiveness  Reynolds averaged Navier-Stokes simulation  Detached-Eddy simulation  Film cooling

摘要:

为了分析缝槽平板振动气膜冷却传热规律，采用基于Reynolds Averaged Navier-Stokes(RANS)和Detached-Eddy Simulation (DES)的CFD动网格仿真分析方法，研究了不同振动频率、不同振幅、不同吹风比及剪切涡结构振动的绝热壁面有效温比。结果表明:(1)在低频(f=100Hz)下，振动有利于提高换热面绝热壁面有效温比；但在高频(f=10kHz)下，振动降低了换热面绝热壁面有效温比。(2)相比频率，振幅对绝热壁面有效温比影响更大；在中频(f=1kHz)下，振动绝热壁面有效温比小于稳态绝热壁面有效温比；不同吹风比(M=0.7， 1.2， 1.9)对绝热壁面有效温比影响趋势基本一致。(3)相比基于RANS的振动仿真方法，基于DES的振动仿真方法能更详细地模拟混合层剪切涡结构流场信息，能更好地反映剪切涡结构对壁面换热效果的影响。

Abstract:

In order to identify the heat transfer of slot plat film cooling under slot vibrating conditions， the adiabatic film effectiveness over a slot plat at different vibration frequencies， vibration amplitudes， blow ratios and shear vortex of the mixing layer was analyzed using CFD dynamic meshing approach based on Reynolds averaged Navier-Stokes(RANS) and Detached-Eddy Simulation(DES). The results show that: (1)Under low vibration frequency (f=100Hz)， the slot vibration increases the adiabatic film effectiveness of heat transfer surface; While under high vibration frequency (f=10kHz)， the slot vibration decreases the adiabatic film effectiveness of heat transfer surface. (2)Under general vibration frequency (f=1kHz)， the adiabatic film effectiveness is weakened by vibration， what’s more， the adiabatic film effectiveness is affected more significantly by vibration amplitude than by vibration frequency. The different blow ratios(M=0.7， 1.2， 1.9) keep almost the same influence on the adiabatic film effectiveness. (3)Compared to RANS method， DES approach performs more efficiently in predicting structure of shear vortex， and better reflects of shear vortex on adiabatic film effectiveness under slot vibration condition.