通道参数对再生冷却通道流动换热的影响

应用RSM模型对冷却通道的流动与换热进行了三维数值模拟,冷却剂为气氢,考虑其物性随温度和压力的变化.所得结果表明:增加壁面粗糙度使冷却剂换热强化,但会增加流阻损失;在突扩突缩区域会出现旋涡,旋涡使局部流阻损失加大且使湍流加强,壁温在旋涡出现处降低;冷却通道内的流动发展不受入口湍流强度的影响;冷却剂离心力引发径向平面内的二次流动,二次流引起的冷却剂质量重新分布使传热在凹曲率段强化,凸曲率段恶化. 

Effects of cooling channel parameters on flow and heat transfer in regenerative cooling channels

Abstract: For studying the effects of wall roughness,sudden expansion /contraction,inlet turbulence intensity and cooling channel curvature on heat transfer and fluid flow in cooing channel, three dimensional turbulent fluid flow and heat transfer were numerically investigated with RSM model which is used to represent the turbulence,the coolant was gas hydrogen, whose thermophysical properties are varied with both temperature and pressure.The results show that the increase of wall roughness will increase not only the heat transfer but also the pressure loss;the vortex appears on the nearby sudden expansion/contraction point, the turbulence intensity and local pressure loss increase due to the vortex at the place it appears,while the wall temperature decreases;the coolant inlet turbulence intensity has no effects on the development of flow in cooling channel;the secondary flows which develop due to centrifugal force on the coolant will cause the mass redistribution which let the heat transfer enhancement at the concave cooling channel while deteriorate at convex cooling channel.