基于晶格Boltzmann方法的接触角实时测量研究

Research on Real Time Measurement of Contact Angle Based on Lattice Boltzmann Method

接触角在表面湿润、毛细现象和移动接触线等问题中是基本的特征量。虽然数值计算中已经可以有效地模拟接触角现象,但是在动态模拟中,接触角还不能被实时地精确测量。基于化学势晶格Boltzmann方法,本文设计一种几何的方法实时测量接触角。当忽略重力的影响时,该方法计算结果与球冠模型的理论预期保持一致,而且不受液滴大小的影响;当考虑重力影响时,虽然液滴呈现明显的变形,但是测量所得的微观接触角保持不变,与理论预期相符。当基板倾斜时,液滴的前进角逐渐增大,后退角逐渐减小,接触角迟滞越来越大,而且能够被实时地测量。

The contact angle is the basic feature in the surface wetting,capillary phenomena and moving contact lines. Although the numerical calculation is able to effectively simulate the contact angle phenomenon, in the dynamic simulation,the contact angle can not be accurately measured in real time. Based on the chemical potential lattice Boltzmann method, a geometric method is designed to measure the contact angle in real time. Under the condition of neglecting gravity, the calculated results are consistent with the theoretical expectations of the ball crown model and the results are not affected by the droplet size. Under the consideration of gravity conditions, although the droplets show significant deformation, the measured micro-contact angle remains unchanged, consistent with the theoretical expectations. When the substrate is tilted,the advancing angle of the droplet gradually increases and the receding angle decreases gradually. The method can measure the dynamic contact angle hysteresis in real time.