Finite difference-based lattice Boltzmann simulation of natural convection heat transfer in a horizontal concentric annulus

In this paper, a finite difference-based lattice BGK model for thermal flows is proposed based on the double-distribution function approach. We applied this model to simulate natural convection heat transfer in a horizontal concentric annulus bounded by two stationary cylinders with different temperatures. Velocity and temperature distributions as well as Nusselt numbers were obtained for the Rayleigh numbers ranging from 2.38 × 10³ to 1.02 × 10⁵ with the Prandtl number around 0.718. It is found that the numerical results are in good agreement with the experimental and numerical results reported in the literature.