Mathematical modelling of conjugate heat transfer and fluid flow inside a domain with a radiant heating system

This study deals with the numerical investigation of combined heat transfer by conduction, turbulent natural convection, and surface thermal radiation in a closed square air-filled cavity with a local radiant heater. The turbulent flow was computed within the quasi (pseudo) direct numerical simulation approach. The governing equations were solved by means of the finite difference method. Developed numerical code was validated by comparison of temperature profiles obtained experimentally and numerically. The effect of time, buoyancy force, walls emissivity, and emitter height on local and mean heat transfer characteristics was studied. For the first time it was found that the mean convective Nusselt number at the bottom solid-fluid interface was slightly altered in the cavity with the local radiant heater when varying the governing parameters. An increase in the Rayleigh number led to a significant rise in the overall temperature. The isotherms and streamlines were significantly altered with time. However, the mean radiative Nusselt number was slightly changed over the time.