Surface radiation with conduction and natural convection in a two-floor enclosure

Surface radiation with conduction and convection in a heated two-floor encl osure is investigated experimentally and theoretically. A model based on th e net-radiation method is employed to compute the radiation exchange betwee n the surfaces including the heater surfaces. The radiation model assumes o paque, diffuse and gray surfaces, a nonparticipating medium, and uniform ra diation fluxes and temperature. The view factors are obtained by using the reciprocity relations and numerical integration. The wall heat transfer rat es by radiation, convection, and conduction were computed for the closed an d open enclosures and for two different heat input rates of 300 W and 600 W . An experimental study was carried out to measure the internal and externa l surface temperatures of the walls, surface temperatures of the heater, an d air temperatures. These temperatures were used in the calculations. The s pecial emphasis is given to the effect of through-flow on the wall heat tra nsfer mechanism. The results show that the effect of through-flow on the wa ll heat transfer is significant. Also, the results indicate that the heat t ransfer from or to the enclosure walls is mainly by convection. However, as a result of the heater position, the energy exchange by radiation becomes significant for the lower compartment walls. (C) 2000 Elsevier Science S.A. All rights reserved.