沟槽表面液滴动力学的格子玻尔兹曼模拟

Lattice Boltzmann simulation of droplet dynamics on groove surfaces

针对液滴在微结构表面上的润湿行为及各向异性浸润行为,采用格子玻尔兹曼方法模拟研究了沟槽表面尺寸、液滴尺寸及重力场对液滴动力学行为的影响.结果表明,垂直接触角大于平行接触角,且与肋板宽度成反比,随沟槽宽度的增加先增大后减小,平行接触角则与沟槽表面尺寸无关.液滴半径、液滴接触角和壁面固体分数相互关联,且壁面固体分数、液滴半径和重力系数与液滴变形比成正相关关系.液滴沿垂直沟槽方向上的铺展运动具有较大的能量壁垒,呈现各向异性浸润行为.液滴半径的增大和重力场的增强均可削弱液滴的各向异性浸润行为,并可通过改变壁面固体分数达到改变液滴状态的目的.

For the wetting behaviors and anisotropic wetting behaviors of droplets on micro-structured surfaces,the effects of the groove surface size,the droplet size and the gravity field on the dynamic behaviors of droplets were simulated and studied by the lattice Boltzmann method.The results show that the vertical contact angle is greater than the parallel contact angle and inversely proportional to the rib width.It increases first and then decreases with the increase of the groove width.However,the parallel contact angle is independent of the groove surface size.The droplet radius,the droplet contact angle and the wall solid fraction are correlated with each other.The wall solid fraction,the droplet radius and the gravity coefficient are positively correlated with the droplet deformation ratio.The spreading motion of the droplet along the vertical groove direction has a large energy barrier and exhibits an anisotropic wetting behavior.The increase of the droplet radius and the gravity field can weaken the anisotropic wetting behaviors of the droplet.The change of the droplet state can be achieved by changing the wall solid fraction at the wall.