润湿性梯度驱动液滴运动的格子Boltzmann模拟

运用考虑了固体与液体间分子作用力的格子Boltzmann方法，数值研究了由于固液界面上表面张力梯度引起的Marangoni效应驱动的液滴运动.当表面张力梯度较小时，计算结果和前人的理论预测符合较好.而表面张力梯度较大时，由于液滴不变形和准平衡态等假设不再满足，理论预测的液滴运动速度高于数值模拟的结果.计算结果显示，在向亲水端运动过程中液滴内部出现旋涡结构，当润湿性梯度较大时，其前进速度和接触角随时间变化出现振荡.

Lattice Boltzmann simulation of droplet motion driven by gradient of wettability

The lattice Boltzmann method is used to simulate numerically the droplet motion driven by Marangoni effect, which is induced by surface tension gradient on the solid-liquid interface, with the consideration of interaction between solid and liquid molecules. The computation results are well compared with the theoretical prediction available for smaller surface tension gradient, whereas the translation velocity of droplet is smaller than the theoretical value for larger gradient, because some assumptions, such as the quasi-equilibrium and non-deformable droplet, are not satisfied in the theoretical analysis anymore. Vortical structure with a solid-like core is found in the droplet when it moves to the hydrophilic end. The variations of velocity and contact angle of droplet are found to be oscillating with time for larger gradient of wettability.