Natural convection from discrete reactions on the bottom wall of an enclosure

Natural convection resulting from discrete reactive heat sources on the bottom wall of an enclosure is investigated. The rest of the bottom wall apart from the heat sources, the top wall, and the vertical walls are kept at the surrounding temperature. The remarkable findings, which have not been reported in any study, are that the flow field and temperature distribution are quite distinct depending on the odd and even number of reactive heat sources on the bottom wall. For odd numbers of heat sources, the vortices have a quite sharp corner near the center of the middle source and the base of the thermal plume is in the middle heat source. Contrary to this, for even numbers of reactive heat sources, the vortices have a blunt corner near the middle two heat sources and it seems that the thermal plume evolves from the coalescence of the middle two heat sources. Whatever the number of heat sources, for increasing the Rayleigh number, the maximum value of the stream function increases and the maximum temperature decreases. However, both of them are increased for higher values of the Frank–Kamenetskii number. It is also observed that the heat loss to the environment through the walls of the enclosure is stronger with the increase in the Rayleigh number and Frank–Kamenetskii number.