格子Boltzmann方法模拟泡沫金属内相变材料热传导融化传热过程

Lattice Boltzmann simulation of conduction melting of phase change materials in metal foams

基于局部热非平衡条件下泡沫金属内热传导融化相变传热的非线性双温度方程,在表征单元尺度上构建双温度分布函数格子Boltzmann模型,其中相变非线性源项处理采用焓法迭代求解。数值模拟了金属骨架与相变材料的温度分布情况,重点分析了孔径、金属骨架与填充材料热传导比和Stefan数等对局部热非平衡效应的影响。模拟结果表明,孔径越大、金属骨架与填充材料热传导比越大,局部热非平衡效应越明显;相变过程的存在,加大了局部热非平衡效应,并且Stefan数越低局部热非平衡效应则越大。

A lattice Boltzmann model under local thermal non-equilibrium conditions based on double temperature equations is developed for simulation of melting governed by heat conduction of phase change materials in metal foams.Nonlinear phase change aspects are tackled by an enthalpy based method.The numerical simulation results show the non-equilibrium effect can not be neglected when the porous metal foam is with low porosity density,when the thermal conduction difference between the fluid and the porous metal foam is significant,and when the Stefan number of phase change material is relative small.