中文摘要：

针对乙醇吸收CO2过程中，由CO2通过界面向液体乙醇传递所导致的Rayleigh对流现象的模拟，建立了二维格子Boltzmann方法（LBM）。采用浓度分布函数和流体质点密度函数的双分布模型格子Boltzmann方法，同时引入由浓度差导致的重度差作为外加力，实现了流体中浓度场与速度场的模拟。应用所建立的LBM方法，对界面具有多个离散CO2扩散源的二维区域液相Rayleigh对流现象进行了模拟，结果显示，模拟得到的浓度分布结构与文献中实验结果相一致。通过考察Rayleigh对流和浓度分布结构，分析了Rayleigh对流存在条件下的传递规律。通过采用LBM方法对浓度场模拟可以定量给出液相界面瞬时传质通量。计算结果表明，瞬时传质通骨晡时间的增长先增加后减小．汶种蛮化与Rayleigh对流结构殛苴蛮化讨程有关．

英文摘要：

In an interracial mass transfer process, the concentration gradient of the transferred component builds up in the vicinity of the interface. The concentration gradient may generate density difference near the interface. If the density gradient directs opposite to the gravity, the interface is known as in Rayleigh instability and Rayleigh convection may occur in case of perturbalion. Rayleigh convection is an interfacial phenomenon usually observed in mass transfer processes and in material processing industries. In this study, a two-dimensional lattice Boltzmann method （LBM） is implemented for simulating Rayleigh convection, which is induced by interfacial mass transfer in the CO2 absorption into liquid ethanol. The computations of concentration and velocity fields are based on a two-distribution model, which consists of the concentration and the density distribution functions of fluid particles in the lattice Boltzmann method. And the gravity difference due to the concentration difference is introduced into the model as external force. The established method is used for the simulation of two-dimensional liquid-phase Rayleigh convection induced by multiple discrete diffusion sources of CO2 on the gas-liquid interface. The simulation results show that the concentration contours are consistent with the experimental results in literature. The effects of Rayleigh convection on the transport mechanisms are investigated by analyzing the Rayleigh convection and concentration contour patterns. By simulating the concentration field with the LBM, the instantaneous interfacial mass transfer flux of CO2 can be obtained. It is demonstrated that when the Rayleigh convection occurs, the instantaneous interracial mass transfer flux increases in the beginning and then decreases with time. Such behavior may be affected by the Rayleigh convection patterns and their evolutions.