Numerical hybrid thermal MRT-LBM for condensation and boiling phenomena on horizontal walls of different wettability

Abstract

In this paper, boiling and condensation phenomena are described on walls with mixed wettability using a hybrid thermal model with multiple relaxation times of the Boltzmann lattice type. We start this study by validating our code. To do so, different simulations are performed namely the spreading of a liquid droplet on an adjustable wettability surface by varying its density, the surface tension for different temperatures around the critical point using Laplace's law which is used to compute the characteristic parameters (Taylor wavelength λ_d, characteristic length l_0 and characteristic time t_0), the evaporation of a liquid droplet to compare it with the work of Zheng et al. [1] for constant thermal conductivity values. Subsequently, the power law is verified according to the literature [2] of the growth of a liquid droplet for three different cases of wettability. On the other hand, we study the behavior of condensation and boiling processes and their interactions between the boundaries of the solid surface in which they occur. For this purpose, the cavity walls are considered wetting in some areas and non-wetting in others. The results show different behaviors depending on the zones of the walls.