应用改进的格子玻尔兹曼自由能模型，对大密度比的溴化锂溶液中不同初始位置和不同大小的双气泡运动进行模拟，获得其密度场与速度矢量分布及其运动规律：大小相同、水平距离一定的双气泡在上升过程中出现先靠近再分离的两个阶段，与初始相对高度无关；大小不同的两气泡在上升过程中可能发生融合或分离，这主要取决于小气泡靠近大气泡时所在大气泡尾迹区的位置，若大小气泡融合，则融合后的气泡速度减小.

By using the improved lattice Boltzmann free energy model, the motion simulation of couple bubble with different initial positions and sizes was carried out in high density lithium bromide solution, and the density and velocity vector distribution and motion of bubbles were obtained. Results show that for two bubbles with same size and a constant distance, the rising process consists of two steps, as closing firstly and then separating, however, the initial relative height has no influence on the process. Two bubbles with different size may coalesce or separate, which depends on the position of wake region of large bubble when the small bubble closes to the latter. If the large and small bubbles coalesce, the new bubble velocity decreases.