液滴撞击液膜过程气泡卷吸的FTM数值模拟

Numerical Simulation for bubble entrapment during drop impacting on liquid film with FTM

中文关键词: 液膜  卷吸现象  两相流  数值分析

英文关键词: Liquid Film  Entrapment Phenomenon  Two-phase Flow  Numerical Analysis

中文摘要:

      采用界面追踪法（Front Tracking Method，FTM）对液滴撞击液膜形成的气泡卷吸现象进行直接数值模拟，分析不同无量纲液膜厚度（H*）和不同Bo数对卷吸气泡出现时间和消失时间的影响。结果表明：在Bo=4时，H*的增加会使得卷吸气泡出现和消失的时间提前，并且在H*＞ 0.415时，卷吸气泡不再出现；在H*分别为0.25和0.15时，卷吸气泡不再出现的临界Bo数分别为3.5765和3.1949，但不同的H*对卷吸气泡出现和消失的时间的影响与固定Bo数时趋势一致。

英文摘要:

      Bubble entrapment is a common phenomenon when drop impacts on the solid substrates and liquid film. Front Tracking Method(FTM), a direct numerical simulation method which can track interface accurately, is used to explore entrapment after drop impacting on liquid film. The effect of different non-dimensional film thickness (H*) and Bo on the starting and losing time for bubble entrapment is discussed. The results shows at Bo=4, the thicker the liquid film is, the earlier the bubble entrapment is; and the existential time is shorter. However, bubble entrapment doesn’t exist anymore when non-dimensional film thickness is great than 0.415. And bubble entrapment is also related with Bo. When H*=0.25, 0.15, the critical Bo value of bubble entrapment disappearing forever is 3.5765 and 3.1949, respectively. Obviously, the smaller H* is, the smaller the critical Bo is. However, the influence of film thickness is the same as fixed Bo value, which the starting and losing time of entrapment is affected by non-dimensional film thickness.