基于格子玻尔兹曼方法的低We数液滴铺展凝固模拟研究

Simulation of droplet spreading and solidification at low We number by lattice Boltzmann method

为了研究3D喷墨打印中液滴在壁面的铺展、凝固现象与机理,基于格子玻尔兹曼方法(Lattice Boltzmann method,LBM),建立了三维多组分相变模型,模拟计算了单液滴在低We数条件下与低温基板碰撞后的演变过程。在模拟过程中考虑了壁温、壁面润湿性等因素对于液滴的铺展、凝固的影响。模拟结果表明,在非润湿性壁面,液滴铺展产生震荡阻尼现象,通过改变壁温控制液滴凝固速度可以达到阻碍或者促进液滴铺展;而在润湿性壁面,凝固会阻碍液滴铺展,液滴最终铺展因子随接触角减小而降低,并且与壁温成正比关系。此外,壁温在低于一定范围后才会对液滴形貌(铺展因子、接触角)造成明显影响。

In order to study the spreading and solidification of the droplet on the substrate in 3D inkjet printing,a three-dimensional multi-component phase transition model was established based on the Lattice Boltzmann method(LBM),and the evolution of a single droplet after collision with a low-temperature substrate at low We number was simulated.The effects of substrate temperature and substrate wettability on the spreading and solidification of droplets were investigated in the simulation process.The simulation results show that on the non-wetting substrate,the droplet spreading produces an oscillation damping phenomenon,and the droplet spreading can be prevented or promoted by changing the substrate temperature to control the droplet solidification rate;While on the wetting substrate,solidification will hinder the droplet spreading,and the final spreading factor of droplets decreases with the decrease of contact angle and is proportional to the substrate temperature.Further,the substrate temperature does not affect the morphology(such as spreading factor or contact angle)significantly until it is below a certain range.