三维有序排列多孔介质对流换热的数值研究

利用CFD软件数值研究了颗粒三维有序堆积多孔介质的对流换热问题. 采用颗粒直径分别为14 mm,9.4 mm和7 mm的球形颗粒有序排列构成多孔介质骨架,在多孔骨架的上方有一恒热流密度的铜板. 采用流固耦合的方法研究了槽通道内温度分布和局部对流换热系数的分布以及对流换热的影响因素. 研究结果表明:热渗透的厚度和温度边界层的厚度在流动方向上逐渐增大,并且随流量的增加而减小;当骨架的导热系数比较高时,对流换热随颗粒直径的减小而略有增大;对流换热系数随聚丙烯酰胺溶液浓度的增大而减小,黏性耗散减弱了对流换热. 关键词： 多孔介质 温度场 局部对流换热系数 数值模拟

Numerical study of convection heat transfer in ordered three-dimensional p orous media

Saturated fluid convective heat transfer in ordered three-dimensional porous media has been investigated numerically using a CFD software. Spherical particles with diameters d_p equal to respectively 14, 9.4, 7 mm have orderly arrangements constituting the porous media skeleton. There is a copper plate of constant heat flux density above the porous skeleton. The distribution of temperature and local convective heat transfer coefficient in the channel, as well as factors affecting the convective heat transfer are investigated by the method of fluid-solid coupling. Results show that the thickness of the thermal penetration and the thermal boundary layer increase in the flow direction, and decrease with the flow rate. When the thermal conductivity of the skeleton is relatively high, the convective heat transfer increases slightly with decreasing particle diameter. The convective heat transfer coefficient decreases with the increase in mass concentration of polyacrylamide solution, because the viscous dissipation weakens convection heat transfer.
Keywords： porous media temperature field local convective heat transfer coefficient numerical simulation