Numerical simulation of pressure-driven phase-change in two-phase fluid flows using the Lattice Boltzmann Method

Abstract

The main purpose of the current article is to model the phase-change phenomena within a two-phase liquid-gas flow caused by the pressure variations throughout the computational domain. In industrial applications, this phenomenon is mostly known as the cavitation. A lattice Boltzmann framework with two distribution functions is developed in which one of the distribution functions is used to compute the velocity and hydrodynamic pressure while the other one recovers the modified Cahn–Hilliard equation. Proper forcing terms are applied to the governing equations to physically account for the phase transition due to the pressure variation. Moreover, the density of the gaseous phase may change according to the pressure rise/drop. Firstly, a simple benchmark problem which consists of a cylinder containing a mixture of liquid-vapor at the saturation condition is considered. The mixture quality can be varied due to the pressure rise/drop. The thermodynamic and finite difference solution of the problem is successfully compared with the numerical results. Finally the model is extended to two dimensions to simulate the droplet evaporation and condensation as well as the bubble growth and shrinkage.