Abstract Rayleigh convection has a significant effect on gas-liquid interfacial mass transfer. However, its intensified mechanism has not been clarified so far. In the present work, three-dimensional hybrid Lattice Boltzmann Method-Finite Difference Method (LBM-FDM) was employed to simulate the Rayleigh convection emerging in the CO2-ethanol absorption process. A gas phase random disturbance model was applied to represent the disturbances on the gas-liquid interface which effectively induces Rayleigh convection. Then the front view images obtained by three-dimensional simulation were compared to the Schlieren observations for validation. Finally, a theoretical mass transfer coefficient model based on dissipation rate of concentration variance was proposed, by analyzing the overhead view of concentration contour and dissipation rate of concentration variance contour. Compared to the small eddy model and surface divergence model, the proposed model shows its strength in determining molecular diffusion stage and convective mass transfer stage of Rayleigh convection process, as well as eliminating the phase difference in model prediction.

中文翻译：

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使用混合LBM-FDM及其传质系数模型的瑞利对流气液界面传质三维数值模拟

摘要 瑞利对流对气液界面传质具有显着影响。但其强化机制至今尚未阐明。在目前的工作中，采用三维混合格子玻尔兹曼法-有限差分法 (LBM-FDM) 来模拟 CO2-乙醇吸收过程中出现的瑞利对流。应用气相随机扰动模型来表示气液界面上的扰动，有效地诱发瑞利对流。然后将通过三维模拟获得的前视图图像与纹影观察进行比较以进行验证。最后，提出了基于浓度方差耗散率的理论传质系数模型，通过分析浓度等高线的俯视图和浓度方差等高线的耗散率。与小涡模型和表面发散模型相比，该模型在确定瑞利对流过程的分子扩散阶段和对流传质阶段以及消除模型预测中的相位差方面显示出其优势。