Numerical simulation of droplet evaporation on a hot surface near Leidenfrost regime using multiphase lattice Boltzmann method

In the present article, evaporation of a liquid drop spreading on hot surface, based on the lattice Boltzmann method, is simulated. Liquid and gas phases are considered to be incompressible. The divergence-free condition of the velocity field is no longer satisfied since the phase change occurs at the interface. In order to take into account the vaporization effects, the convective Cahn-Hilliard equation is extended. The phase change process is modeled by employing a proper source term at the interface. The D2Q9 structure is used in the present simulation. Effects of different non-dimensional parameters including the Bond number, liquid Archimedes number, gas Stefan number, density ratio, and the Prandtl number on behavior of liquid drop are investigated. Computational results showed that increasing the Bond number, liquid Archimedes number and density ratio accelerates the evaporation rate. The Leidenfrost regime is observed in high Stefan numbers, while in low Stefan numbers, the drop is attached to the heated wall. Furthermore, decreasing the equilibrium contact angle leads to the lagging of the Leidenfrost regime.