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对不同物性骨架对固液相变过程的影响研究可为中低温相变储能技术的应用和发展奠定理论基础。文章基于格子玻尔兹曼方法(LBM),采用两区域焓—多孔介质模型研究了方腔内无填充多孔介质骨架固液相变过程,从孔隙尺度分析了相变过程的流动和传热机理,探讨了方腔内填充不同导热系数的骨架对于相变过程的影响。结果表明:在无填充多孔介质骨架方腔内固液相变过程中传热方式由热传导逐渐向自然对流换热转变,形成向右倾斜的糊状区;它的存在导致相变材料不能完全融化,且在方腔的左侧壁面处存在上窄下宽的固相相变材料;在填充多孔介质骨架方腔内,融化的初始阶段,高导热系数多孔骨架的相变材料融化速率较大,对相变换热起到了明显的促进作用,而当相变过程发展至准稳态阶段,受到右壁面处的低温影响和糊状区的综合作用,相变过程受到明显的抑制,且骨架的导热系数越大,其融化率越低。
The research on the influence of skeletons with different physical properties on the solid-liquid phase change process can lay a theoretical foundation for the application and development of low-temperature phase change energy storage technology. Based on the lattice Boltzmann method (LBM), a two-region enthalpy-porous media model was used to study the solid-liquid phase transition of unfilled porous media in a square cavity. The flow and heat transfer mechanism were analyzed from the pore scale The effect of the skeleton filled with different thermal conductivity in the cavity on the phase transformation was discussed. The results show that the heat transfer mode gradually changes from heat conduction to natural convection heat transfer in the solid-liquid phase transition in the cavity of unfilled porous medium, forming a right-inclined paste-like region; its existence can not completely melt the phase change material , And the upper and lower width solid phase change material exists in the left side wall of the cavity; in the initial stage of melting in the cavity of the filled porous medium, the melting rate of the phase change material with high thermal conductivity porous skeleton is larger, Which has a significant promotion effect on the phase transformation heat transfer. When the phase transformation process develops to the quasi-steady state, the phase change process is obviously inhibited by the low temperature at the right wall surface and the combined action of the mushy zone, The larger the thermal conductivity, the lower its melting rate.