CORRELATIONS FOR FREE-CONVECTION AND SURFACE RADIATION IN A SQUARE CAVITY

In the present study the results of a numerical investigation of combined surface radiation and free convection in a square cavity with air as the intervening medium are reported. The computations have been performed for 10(3) less-than-or-equal-to Gr less-than-or-equal-to 10(6), with the emissivities of all the walls varying between 0 and 1. Surface radiation reduces the convective heat transfer across the cavity and at the same time contributes to the overall heat transfer by direct radiant heat transfer across the cavity. This ''dual'' nature of radiation has been qualitatively highlighted in an earlier investigation by the authors. The objective of the present study however, is to give comprehensive correlations for convection and radiation based on the numerical calculations of the coupled problem. The basis for the choice of the form of the various terms in the correlations has also been brought out.