LAUSR

Abstract Heat transfer induced by combined surface radiation and laminar natural convection in an open square cavity heated by three identical isothermal heat sources is studied numerically by using the multirelaxation time scheme of the lattice Boltzmann method. The working fluid is air. The heat sources, separated by adiabatic segments, are mounted on a vertical wall facing the aperture of the cavity and the horizontal walls of the latter are insulated. The parameters governing the problem are the emissivity of the walls (varied from 0 to 1) and the Rayleigh number (varied from to ). The results obtained show that the convective heat transfer outclasses the radiative one even when the emissivity of the walls is high. The disproportionality observed in the cooling rates of the heat sources may be strongly attenuated by the inclusion of radiation in the heat transfer mechanism. Results obtained for the heat transfer from each of the three heat sources and the volumetric flow rate aspired into the cavity are grouped in useful correlations.