A liquid-vapor phase change lattice Botlzmann method was used to simulate the dynamics of two bubbles during the lateral coalescence on solid surfaces in nucleate boiling. The evolution of bubble shapes and the departure diameter of bubbles were compared with experimental data. Comparisons show good agreement. The heat fluxes under nucleating, coalescing, growing and departing bubbles were simulated and directly related to the bubble dynamics. It was found that a typical ebullition cycle includes nucleation and growth of individual bubbles, coalescence of two bubbles, oscillation and departure of the coalesced bubble. The heat-flux variation under the bubbles has two major peaks, which are due to the coalescence of two bubbles, the departure of the coalesced bubble and nucleation of succeeding bubbles, respectively. The results showed that the heat flux peaks for nucleation and departure are slightly larger than the heat flux peaks for coalescence for the smaller and the larger separation distances, while those for coalescence are larger for the moderate separation distances. It was also found that there exists an optimal separation distance for the coalescing bubbles to achieve the best heat transfer performance, which provides very useful information to enhance pool boiling heat transfer.

使用液-汽相变格子 Botlzmann 方法模拟核沸腾中固体表面横向聚结过程中两个气泡的动力学。将气泡形状的演变和气泡的离开直径与实验数据进行了比较。比较显示出良好的一致性。模拟了气泡成核、聚结、生长和离开下的热通量，并与气泡动力学直接相关。发现典型的沸腾循环包括单个气泡的成核和生长、两个气泡的合并、合并气泡的振荡和离开。气泡下的热通量变化有两个主要峰值，分别是由于两个气泡的合并、合并气泡的离开和后续气泡的成核。结果表明，对于较小和较大的分离距离，成核和离开的热通量峰值略大于聚结的热通量峰值，而中等分离距离的聚结热通量峰值较大。还发现聚结气泡存在最佳分离距离以实现最佳传热性能，这为增强池沸腾传热提供了非常有用的信息。