Numerical simulation of evaporation with Rayleigh convection using LBM-FDM hybrid method and proposal of the interfacial mass transfer coefficient model
Numerical simulation of evaporation with Rayleigh convection using LBM-FDM hybrid method and proposal of the interfacial mass transfer coefficient model
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DOI：
10.1016/j.ijheatmasstransfer.2018.12.100
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发表时间：
2019-04
影响因子：
5.2
通讯作者：
Xiaolong Ge;Botong Liu;Botan Liu;Xigang Yuan;Hongxing Wang
中科院分区：
文献类型：
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作者：
Xiaolong Ge;Botong Liu;Botan Liu;Xigang Yuan;Hongxing Wang
在丙酮-乙酸乙酯、异丙醇-水等双溶剂体系中，溶质蒸发可引起瑞利对流。采用LBM-FDM型混合方法，结合液相随机扰动模型，模拟了瑞利对流的爆发及其演变特征。在瑞利对流开始时间、纹影法得到的浓度场和PIV获得的速度场、平均传质系数和沿重力方向的统计平均速度分布等四个方面，模拟结果与实验测量结果吻合较好。结果表明，LBM-FDM型混合方法能有效地捕捉到这一中尺度现象的关键特征。然后提出了三种传质模型：小涡模型、表面散度模型和基于理论参数浓度方差、耗散率和雷诺质量通量的新模型来预测界面传质系数，新模型在瑞利对流开始时间、传质系数峰值和充分发展对流阶段速度场与浓度场的不同步等方面具有明显的优势。新模型从理论上证明了该模型在确定传质系数方面的优越性。
The Rayleigh convection could be induced by solute evaporation in dual solvents, such as acetone-ethyl acetate and isopropanol-water system. The onset of Rayleigh convection and its evolutionary characteristics were simulated using LBM-FDM hybrid method with liquid phase random disturbance model. And the simulation results were in reasonable agreement with experimental measurements in four aspects: Rayleigh convection onset time, concentration field acquired by Schlieren and velocity field acquired by PIV, average mass transfer coefficient, and statistical average velocity distribution along the gravitational direction. It proves that the LBM-FDM hybrid method is effective in capturing the key features in this mesoscale phenomenon. Then three mass transfer model including small eddy model, surface divergence model and the new model based on theoretical parameters concentration variance, its dissipation rate and Reynolds mass flux were proposed to predict the interfacial mass transfer coefficient, and the new developed model had advantages over other two models, in the onset time of Rayleigh convection, the peak of mass transfer coefficient and tackling the non-synchronism between velocity and concentration field in fully developed convective stage. The new developed model shows its strength in determining the mass transfer coefficient in a theoretical way.