The lattice Boltzmann model for the heat and mass transfer of latent functional thermal fluid using enthalpy-transforming method

Abstract

An enthalpy-transforming model based on lattice Boltzmann method is established in this paper to solve incompressible thermal flow problem of latent functional thermal fluid. Using the Chapman-Enskog expansion, the macroscopic conservation equation of enthalpy is obtained by introducing a new type of equilibrium distribution. It is validated by its application to simulate the natural convection of latent functional thermal fluid in a square cavity, which is heated differentially at two vertical side walls. Good agreement was obtained between the present results and those from other works. Furthermore, natural convection of latent functional thermal fluid in two-dimension and three-dimension cases are considered respectively. The influence of Stefan numbers, Rayleigh numbers and phase change temperature on heat transfer was studied. The relative errors of average Nusselt number between the present model and references are less than 2 %. In the case with periodic boundary condition, the present model can reveal heat transfer process of LFTF with different frequencies, amplitudes and volume fractions. The simulation results show that the present model can be used in the flow and heat transfer simulation of latent functional thermal fluid.