基于格子Boltzmann方法的液滴撞击具有不同润湿性孔板的研究

Study on Droplets Impacting on Orifice Plates With Different Wettabilities Based on the Lattice Boltzmann Method

基于格子Boltzmann方法,对液滴撞击不同湿润性节流孔板表面进行了数值模拟.主要研究了在液滴撞击过程中,Weber数(We)、孔板表面湿润性和孔板尺寸对液滴通过孔板时不同状态的影响.数值模拟结果表明:孔板为亲水特性时,在较低We下,液滴不会与孔板表面脱离,而是附着在孔板下表面,并且在毛细作用下液滴会在孔道中上升一段距离,形成液塞现象,在较高We下,液滴会穿过孔板,并发生破裂现象;孔板为疏水特性时,在较低We下,液滴无法穿过孔板,且无法迁移至下表面,最终稳定在孔板孔道上,在较高We下,液滴能穿过孔板,穿过时会发生破裂,孔板上表面会残留液滴.改变孔板尺寸发现,在较小的孔板孔径以及较厚的孔板厚度下,液滴不易通过.

Based on the lattice Boltzmann method, the numerical simulation of droplet impacting on orifice plates with different wettabilities was carried out. The effects of the Weber number(We), the wettability of the orifice surface and the orifice size on different states of droplets passing through orifice plates during impacts were studied. The numerical simulation results show that, different phenomena will occur in the processes of droplets impacting on the orifice plates. If the orifice plate is hydrophilic, the droplet will not detach from the orifice plate surface, but adhere to the lower surface of the orifice plate for a relatively low We number, and then the droplet will rise for a certain distance in the orifice channel under the action of capillarity, forming the liquid plugging phenomenon. For relatively high We numbers, droplets will pass through the orifice plates and rupture will occur. If the orifice plate is hydrophobic, the droplet will not pass through the orifice plate and migrate to the lower surface for a relatively low We number, and will finally stabilize in the orifice channel.For higher We numbers, droplets will pass through the orifice plates, and then break up, leaving droplet remains on the surfaces of the orifice plates. For various orifice sizes, the droplet will be more difficult to pass through the plate for a smaller orifice size or a lager orifice plate thickness.