发汗冷却中流动与换热的数值模拟

NUMERICAL SIMULATION OF FLUID FLOW AND HEAT TRANSFER IN TRANSPIRATION COOLING

本文采用改进的低Re数k-ε模型-低Re数kθ-εθ模型以及局部非热平衡模型,将主流区和多孔壁面区进行耦合,通过数值模拟研究了发汗冷却过程中的流动与换热问题。计算结果表明:多孔壁面中靠近主流区的部分温度梯度很大;随着冷却剂流量的增大,壁面上的最高温度明显下降;就本文所选取的参数而言,在发汗冷却所用的冷却剂的量占总流量的1％左右时,冷却效果非常明显。

The thermal characteristics of the porous wall and the main flow during the period of transpiration cooling are investigated by numerical calculations. The thermal non-equilibrium model is adopted to calculate the thermal field of the porous wall. An improved low Reynolds number k-ε model is adopted to calculate the turbulent velocity field and the thermal field of the main flow. The fluid flow and heat transfer in the main flow and the porous wall are calculated coupled by boundary conditions. The calculation results show that the temperature gradient increases quickly near the transpiration wall. The highest temperature of the transpiration wall descends apparently with the increase of the mass flow rate of the cooling liquid. In the present works, the effect of transpiration cooling is distinct when the blow ratio reaches 1%.