Influence of Heat Sources/Sinks on Unsteady Natural Convection in a Differentially Heated Enclosure

Numerical simulations were performed using the Lattice Boltzmann Method to investigate natural convection heat transfer in an annulus system. The system consisted of an air-filled square cavity, with differential heating, and contained circular-shaped isothermal pairs serving as heat sources/sinks. The study examined the influence of various Rayleigh numbers ( \(10^{3}\) to \(10^{6}\) ) and different arrangements of cylinders within the cavity on heat transfer characteristics. The code's accuracy was confirmed by validating it with various instances of natural thermal flows. These included scenarios such as natural convection in a triangular cavity with a heated circular cylinder, natural convection in a concentric annulus, and natural convection in a square cavity with a heated circular or elliptical cylinder. The findings emphasize the notable influence of cylinder arrangement on heat transfer within the enclosure.