【摘要】 采用控制容积法与蒙特卡罗法对圆管层流入口段参与性介质的辐射-对流耦合换热进行了数值模拟研究. 在对流-扩散项的离散中,分别采用了一阶差分的指数格式与二阶差分的QUICK格式. 通过模拟计算,比较分析了两种差分格式的结果差别,考察了入口段耦合换热的温度场、径向导热热流场以及对流换热壁面热流与努谢尔数的分布特征. 研究表明,入口段速度边界层发展对势流区的排挤效应对耦合换热有明显影响,采用QUICK格式能够模拟这一现象,而一阶差分格式不能,后者过高地估计了对流换热强度;辐射换热在抑制对流换热作用的同时,使两种差分格式的模拟结果呈现偏差的区域由入口附近向出口方向扩展.更多还原

【Abstract】 By the control volume method and the Monte Carlo method, the coupled radiative-convective heat transfer of participating medium in laminar entrance flow in tubes is investigated numerically. The QUICK scheme of second-order difference and the exponential scheme of first-order difference are employed in discretization, respectively. The numerical results under the two difference schemes are compared. The temperature field, the heat flux of radial conduction, the wall heat flux and the Nusselt number distribution are presented and discussed for the coupled heat transfer. The results show that, the local axial acceleration effect in velocity boundary can influence the coupled heat transfer. The QUICK scheme can simulate this phenomenon, but the first-order scheme can’t. In addition, the latter scheme evaluates the convection effect excessively. The radiative heat transfer weakens the convection effect and enlarges the region where the numerical results under the two difference schemes show obvious difference.更多还原