混合长度理论的改进及其在变物性传热中的应用  

IMPROVEMENT OF THE MIXING LENGTH THEORY AND ITS APPLICATION TO VARIABLE-PROPERTY HEAT TRANSFER

作　　者：毛宇飞[1] 白博峰[1] 郭烈锦[1] 

机构地区：[1]西安交通大学动力工程多相流国家重点实验室,陕西西安710049

出　　处：《工程热物理学报》2011年第1期58-62,共5页Journal of Engineering Thermophysics

基　　金：国家自然科学基金重点项目(No.50536020);创新群体项目(No.50821064)

摘　　要：根据边界层理论,对管内变物性湍流强制对流换热控制方程组进行简化;并通过考虑湍流输运中的密度脉动,对传统的混合长度湍流模型进行改进,使之能同时适用于常物性流动和变物性流动。基于该计算模型,对管内超临界压力水湍流对流换热特性进行了数值模拟。计算结果表明,本文的计算模型能正确地反映出超临界工况下的变物性对流换热特征,换热系数预测值与相应实验数据符合良好,并且计算过程极为高效。The governing equations for variable-property turbulent forced convection heat transfer in tubes were simplified according to the boundary-layer theory.And an improved mixing length turbulence model was developed by introducing the effect of density fluctuations into the equations of turbulent transport,which can be applied to both constant-property and variable-property flows.Based on the proposed calculation models above,numerical simulations were carried out to investigate the turbulent convective heat transfer of water flowing in tubes at supercritical pressures. The simulated results showed that the present calculation models can reproduce the heat transfer characteristics exhibited in the experiments for variable-property flows at supercritical pressures.The predicted heat transfer coefficients were in good agreement with the experimental results and the calculation was performed with high efficiency.

关 键 词：变物性 超临界 混合长度 对流换热 

分 类 号：TK124[动力工程及工程热物理—工程热物理]