二元液滴自由碰撞聚并后的振荡行为研究

以甲苯、超纯水为多相系统研究对象,采用高速摄像机测试分析了二元液滴自由碰撞聚并后的振荡行为特性。实验结果表明,聚并后甲苯液滴振荡过程存在明显的周期性与阻尼衰减机制,液滴Reynolds数、Weber数是影响聚并后液滴振荡周期、阻尼系数的关键无量纲参数。液滴惯性力与振荡周期呈正相关性,而液滴黏性力则主导了振荡过程的阻尼衰减机制,振荡阻尼系数随黏性力的增加而增加,同时,液滴碰撞聚并作用与其后续振荡过程相对独立,即碰撞聚并过程对液滴振荡行为特性无明显影响。此外,液滴振荡过程特性参数的实验与理论计算对比结果显示,振荡周期实验结果相较于理论值略微偏高,振荡周期、阻尼系数实验与计算值相对误差的标准差分别为14.9%和44.9%。

Investigation on droplet oscillatory behavior after free binary collision and coalescence

Toluene and ultrapure water were used as the research object of the multiphase system. The high-speed camera test was used to analyze the oscillation behavior of binary droplets after free collision and coalescence. The experimental results show that the oscillation process of toluene droplets after coalescence has obvious periodicity and damping attenuation mechanism, and the Reynolds number, Weber number of droplets are the key dimensionless parameters affecting the process. There is a positive correlation between the inertial force and the oscillation period, while the viscous force dominates the damping attenuation mechanism of the oscillation process. It indicates that the damping coefficient increases with the increasing viscous force. At the same time, the collisional coalescence of droplets is relatively independent of its subsequent oscillation process, which means the collisional coalescence process has no obvious effect on the oscillation behavior of the droplet. In addition, the experimental and theoretical comparison show that the experimental results of the oscillation period are slightly higher than the theoretical values. In general, the standard deviations of the relative errors between experiment and calculation are 44.9% and 14.9% for the damping coefficient and oscillation period, respectively.