A numerical study on droplet impingement onto a thin liquid film by using a pseudo-potential LB method

An improved pseudo-potential Lattice Boltzmann Method (LBM) is employed for simulating the two-phase flow induced by a liquid droplet impinging onto the film of the same liquid on solid surface. In this paper, the Kupershtokh exact difference method (EDM) and the Carnahan-Starling equation of state are coupled in the pseudo—potential multiphase lattice Boltzmann model, which is suitable for simulation of high liquid/vapor density ratio multiphase flows. Based on the results the model is suitable forsolution of two phase flow problem at a high density ratio of liquid to vapor. The role of the film thickness and the Reynolds number are discussed. The numerical method agrees well with a popular analytic solution (the Laplace’s law). Crown radius and crown height evolutions for various Reynolds numbers at different liquid film thickness are compared. The maximum crown height and its corresponding time using the model for different Reynolds numbers and various film thicknesses are calculated. The timehistory of the spread factor of the liquid sheet emitted immediately after the droplet impact also follows the known spreading power law.