Abstract

This work numerically presents the study of flow and heat transfer in a rectangular channel partially filled with porous media at the pore scale using lattice Boltzmann method. Quartet structure generation set is adopted to generate the structure of porous media. The effects of the relative height, porosity and specific surface area of porous media on the fluid flow and the Nusselt number are investigated in detail. The simulation results indicate that there exists a relative height of porous media where the Nusselt number and average dimensionless velocity are both up to their maximums; dimensionless velocity and Nusselt number slightly increase with the increment of porosity at small specific surface area, but have no significant change at large specific surface area; the increase rates of dimensionless velocity and Nusselt number with the increment of specific surface area decrease as porosity decreases. Based on the simulation results, correlations of Nusselt number with the fluid flow in the zone adjacent to porous media and the characteristic of porous media are established.

摘要

这项工作在数值上展示了使用格子玻尔兹曼方法在孔隙尺度上部分填充多孔介质的矩形通道中的流动和传热研究。采用四重结构生成集生成多孔介质的结构。详细研究了多孔介质的相对高度、孔隙率和比表面积对流体流动和努塞尔数的影响。模拟结果表明，多孔介质存在一个相对高度，努塞尔数和平均无量纲速度均达到最大值；无量纲速度和努塞尔数在小比表面积下随着孔隙率的增加略有增加，但在大比表面积下没有显着变化；随着比表面积的增加，无量纲速度和努塞尔数的增加率随着孔隙率的减小而减小。在模拟结果的基础上，建立了努塞尔数与多孔介质邻区流体流动的相关性以及多孔介质的特性。