Numerical investigation of combined force convective–radiative heat transfer in a horizontal channel with lattice Boltzmann method

Abstract

To simulate heat transfer processes, there are numerous numerical methods available; in the meantime, the lattice Boltzmann method is a novel method for analyzing a type of engineering problem that has been very much considered. In the present study, to analyze the heat transfer problem of fluid flow between two horizontal parallel planes and solve the governing equations, such as momentum equations, energy and radiation transfer, the lattice Boltzmann method was used, whereas energy and momentum equations are solved by two relaxation time models to increase stability in the lattice Boltzmann method. For radiation intensity, the radiative transfer equation is solved by the single relaxation time model, and then radiation flux divergence is added into the energy equation. The geometry governing the problem is a horizontal and two-dimensional channel with constant temperature walls. After explaining the lattice Boltzmann method and solving governing equations, the results were validated, and the effect of radiation heat transfer parameters (Planck number–Optical thickness–Scattering albedo) on the heat transfer problem for fluid flow between two horizontal plates was determined. By examining the impact of the related parameters, it was found that increasing the optical thickness, decreasing the Planck number and reducing the scattering albedo tend to enhance the effect of radiative heat transfer. More importantly, the optical thickness parameter has the most influence on the radiative heat transfer.