中文摘要：

液滴撞击壁面时，液滴与壁面问产生的气泡及其变化对液滴在壁面上的后续运动具有重要的影响。利用相界面追踪的复合Level Set-VOF方法和壁面润湿模型，通过气液两相流动与固壁相互作用的耦合求解，对液滴撞击壁面时气泡的产生及运动进行了研究。研究结果表明，撞击速度较大时，液滴与壁面间气体的压力远大于液滴内压力以及接触线附近区域液体和气体具有不同的速度分布特性是撞击壁面时液滴内产生气泡及气泡运动变化的主要原因；液滴与壁面间形成的气体层宽度将经历先增大后减小，并最终在液滴中心形成一个气泡的变化历程。液滴撞击速度小于一定值时，气泡最终半径与撞击速度呈近似线性关系，撞击速度对气泡最终半径影响较大；撞击速度超过一定值后，气体层最大宽度与撞击速度呈近似线性关系，但气泡最终半径基本不再受撞击速度的影响。

英文摘要：

The generation and movement of the bubble inside a droplet affect the movement of the droplet intensively when the droplet impacting on a wall. The generation and movement mechanism of the bubble inside an impacting droplet are researched by the coupled solution of the coactions of gas-liquid two-phase flows with wall, based on the combined Level Set-VOF method for gas-liquid interface tracking and the wall wetting model. The results show that the pressure between the droplet and wall far bigger than the pressure inside the droplet and the different velocity distribution of the liquid and gas beside the contact line are the primary causes of the bubble generation and movement when droplet impacting on a wall. The liquid layer width experiences an increase process first and then decrease, and finally forms a bubble. The final bubble diameter increases linearity with the impacting velocity and is affected intensively by the velocity when the impacting velocity is smaller than certain value. The maximum liquid layer width increases linearity with the impacting velocity, while the impacting velocity affects the final bubble diameter weakly when the impacting velocity is bigger than certain value.