A new thermal lattice Boltzmann model for liquid-vapor phase change

TL;DR

This paper introduces a simplified thermal lattice Boltzmann model for liquid-vapor phase change that avoids complex temperature gradient calculations, improves efficiency with a D2Q5 lattice, and is validated through evaporation and boiling simulations.

Contribution

It presents a novel thermal lattice Boltzmann model that simplifies calculations and enhances computational efficiency for phase change problems.

Findings

Accurately simulates droplet evaporation and boiling.

Achieves good agreement with analytical and finite difference results.

Models bubble detachment diameter dependence on gravity.

Abstract

The lattice Boltzmann method is adopted to solve the liquid-vapor phase change problems in this article. By modifying the collision term for the temperature evolution equation, a new thermal lattice Boltzmann model is constructed. As compared with previous studies, the most striking feature of the present approach is that it could avoid the calculations of both the Laplacian term of temperature [$\nabla \cdot \left( {\kappa \nabla T} \right)$] and the gradient term of heat capacitance [$\nabla \left( {\rho {{\rm{c}}_v}} \right)$]. In addition, since the present approach adopts a simple linear equilibrium distribution function, it is possible to use the D2Q5 lattice for the two dimensional cases consided here, making it is more efficiency than previous works in which the lattice is usually limited to the D2Q9. This approach is firstly validated by the problems of droplet evaporation in open space and adroplet evaporation on heated surface, and the numerical results show good agreement with the analytical results and the finite difference method. Then it is used to model nucleate boiling problem, and the relationship between detachment bubble diameter and gravity acceleration obtained with the present approach fits well with the reported works.