冷端边界条件对发汗冷却解析解的影响  

Effects of coolant side boundary condition on analytical transpiration cooling solutions

作　　者：熊宴斌[1,2] 姜培学[1] 祝银海[1] 黄拯[1] 刘元清 

机构地区：[1]清华大学热能工程系,科学与动力工程教育部重点实验室,北京100084 [2]北京宇航系统工程研究所,北京100076

出　　处：《清华大学学报（自然科学版）》2013年第10期1452-1458,共7页Journal of Tsinghua University(Science and Technology)

基　　金：国家自然科学基金重点项目(50736003);国防基础研究计划项目(B1420110113)

摘　　要：发汗冷却多孔区域的非热平衡模型数值计算中,冷端边界条件对多孔介质内流固温度分布有着非常明显的影响。该文针对发汗冷却多孔壁面内部非热平衡模型理论求解方法中冷端边界条件的设置问题,比较了3种不同的冷端边界条件设置模型。结果表明:在流动Reynolds数较小时,假设冷端流体温度等于初始温度的等温边界且假设边界绝热的边界条件会导致冷端附近流固温度偏低;而假设等温边界同时存在冲击冷却边界会使得流固温度整体范围内偏低。该文分析了量纲为1的数对不同边界条件模型计算结果的影响,指出量纲为1的冷却剂流量与多孔体Biot数增加会使流体冷端进口温度等于远端温度假设成立,并提出了热平衡假设成立的条件方程。Analytical solutions for the temperature distributions in the porous media zone in transpiration cooling were developed using the local thermal non-equilibrlum model. Three different boundary condition models were used for the coolant entrance side of the porous media wall. The results show that the solid and fluid temperatures are lower for the isothermal with insulation boundary near the coolant side entrance, while the solid and fluid temperatures are lower through the porous wall for the isothermal boundary with convection heat transfer at the back side. The effects of the dimensionless parameters on the results were analyzed for different boundary conditions. Increasing the dimensionless coolant mass flow rate and Blot number resulted in results for the isothermal boundary condition at the coolant side closer to the results calculated without the temperature assumption. The conditions when the local thermal equilibrium model could be used were discussed with a defining equation. The dimensionless solid and fluid temperature difference increases with increasing coolant mass flow rate or decreasing Blot number, which makes the local thermal equilibrium model inapplicable.

关 键 词：发汗冷却 局部非热平衡 边界条件 理论解 

分 类 号：TK124[动力工程及工程热物理—工程热物理]