  Modeling liquid-vapor phase change using the lattice Boltzmann (LB) method
has attracted significant attention in recent years. In this paper, we propose
an improved three-dimensional (3D) thermal multiphase LB model for simulating
liquid-vapor phase change. The proposed model has the following features.
First, it is still within the framework of the thermal LB method using a
temperature distribution function and therefore retains the fundamental
advantages of the thermal LB method. Second, in the existing thermal LB models
for liquid-vapor phase change, the finite-difference computations of the
gradient terms $\nabla \cdot u$ and $\nabla T$ usually require special
treatment at boundary nodes, while in the proposed thermal LB model these two
terms are calculated locally. Moreover, in some of the existing thermal LB
models, the error term ${\partial _{{t_0}}}\left( {Tu} \right)$ is eliminated
by adding local correction terms to the collision process in the moment space,
which causes these thermal LB models to be limited to the D2Q9 lattice in two
dimensions and the D3Q15 or D3Q19 lattice in three dimensions. Conversely, the
proposed model does not suffer from such an error term and therefore the
thermal LB equation can be constructed on the D3Q7 lattice, which simplifies
the model and improves the computational efficiency. Numerical simulations are
carried out to validate the accuracy and efficiency of the proposed thermal
multiphase LB model for simulating liquid-vapor phase change.
