随机结构多孔介质等效热导率数值计算

本文对二维颗粒弥散多孔介质的辐射导热耦合等效热导率进行了数值计算研究。首先采用随机生成结构方法(Random generate-growth method,RGGM)生成实际多孔材料的复杂结构。在此基础上,采用离散坐标法及有限容积法求解了复杂结构内部辐射导热耦合换热,进而计算得到材料的等效热导率。根据建立的材料随机结构模型及等效热导率数值计算模型,分别研究了衰减系数、弥散相体积分数、温度等因素对材料等效热导率的影响,并将数值计算结果与理论计算结果进行对比,吻合较好,反映出模型用于预测实际多孔材料等效热导率的有效性。

Numerical Calculation of Effective Thermal Conductivity for Complex Multiphase Materials

In this paper,the effective thermal conductivity(ETC)of porous medium which combined heat conduction and radiation was investigated numerically.In order to reflect the actual structure of porous media,a kind of reconstruct technique named Random generate-growth method(RGGM)was introduced to generate stochastic structure of porous media.Then Discrete Ordinate Method(DOM)and Finite Volume Method(FVM)were used to solve the coupled conduction and thermal radiation,and material’s effective thermal conductivity was calculated.Based on the stochastic structures and numerical model,the effects of extinction coefficient,volume fraction of dispersed phase and temperature on heat transfer in porous media and its effective thermal conductivity were investigated.The results were well agreed with the theoretical calculated values,which demonstrates that the model presented in this paper is reliable for practical applications.