液桥蒸发动力学过程的格子Boltzmann数值模拟研究

Lattice Boltzmann Simulation of the Evaporation Kinetics of a Liquid Bridge

摘要: 本文采用格子Boltzmann方法研究了相对湿度、基板宽度和液桥高度对液桥蒸发动力学过程的影响。模拟结果表明，提高湿度可以减小液桥的蒸发速度，延长液桥断裂时刻。增大液桥高度可以提高液桥的蒸发速度，减小液桥断裂时刻。基板宽度对液桥蒸发速度可以忽略，因此液桥断裂时刻不变。在蒸发初期液桥颈部与基板边缘钉扎而液桥腰部收缩，使得液桥与基板间接触角减小，液桥以固定接触线的模式蒸发。当液桥接触角减小到足够小后，液桥接触线与基板边缘脱钉，液桥以固定接触角模式蒸发。环境湿度越大，液桥接触线脱钉所需时间越长。液桥高度越高，液桥接触线脱钉所需时间越短。而基板宽度对液桥接触线脱钉所需时间的影响可以忽略。

Abstract: In this paper, the lattice Boltzmann method was used to study the effects of humidity, substrate width and liquid bridge height on the evaporation kinetics of liquid bridges. The simulation results show that increasing the relative humidity can reduce the evaporation velocity of the liquid bridge and prolong the breaking time of the liquid bridge. Increasing the height of the liquid bridge can increase the evaporation rate of the liquid bridge and reduce the breaking time of the liquid bridge. The width of the substrate has a negligible effect on the evaporation rate of the liquid bridge, so the time of fracture of the liquid bridge remains unchanged. In the initial stage of evaporation, the neck of the liquid bridge is pinned to the edge of the substrate and the waist of the liquid bridge is contracted, so that the contact angle between the liquid bridge and the substrate is reduced, and the liquid bridge evaporates in the mode of fixed contact line. When the contact angle of the liquid bridge is reduced to a small enough level, the contact line of the liquid bridge detaches from the edge of the substrate, and the liquid bridge evaporates in a fixed contact angle mode. The higher the ambient humidity, the longer it takes for the contact line of the liquid bridge to detach. The higher the height of the bridge, the shorter the time required for the contact line of the bridge to detach. However, the influence of the width of the substrate on the time required for the detachment of the contact line of the liquid bridge is negligible.