黏性耗散对幂律流体在多孔介质内对流换热的影响

基于Darcy-Brinkman-Forchheimer流动模型,比较了幂律型非牛顿流体在饱和多孔介质通道内充分发展的强迫对流换热过程中不同黏性耗散的影响,推导出量纲一的轴向流速分布、量纲一的温度分布,及对流换热特征参数的计算表达式,并在恒热流边界条件下,利用经典四阶Runge-Kutta法对不同情形下的黏性耗散效应进行了数值求解.模拟结果表明:对流换热特性与速度分布密切相关,不同的黏性耗散Darcy项、Al-Hadhrami项和Forchheimer项对流动换热特性有重要的影响,且布林克曼数Br、达西数Da、综合惯性参数F和幂律指数n等参数对流动换热特性也有着较大影响.

Influence of viscous dissipation on convection heat transfer of a power-law fluid in porous medium

Based on Darcy-Brinkman-Forchheimer flow model, the influences of different viscous dissipation on fully developed forced convection heat transfer of a power-law non-Newtonian fluid in a saturated porous medium channel were compared. The dimensionless calculation expressions of the axial velocity distribution, temperature distribution and convection heat transfer characteristics were deduced, and the viscous dissipation effects under different cases were solved numerically by employing the classical Runge-Kutta fourth-order scheme subjected to uniform heat flux. The numerical simulation results indicate that the convection heat transfer characteristics are closely related to velocity distribution, and are significantly affected by different viscous dissipation terms, namely the Darcy term, the Al-Hadhrami term and the Forchheimer term, and also are influenced by the relative magnitude of the Brinkman number Br , the Darcy number Da , the integrated inertial parameter F and the power-law index n .