Natural convection heat transfer above square upward-facing horizontal surfaces of constant heat flux in air

Experiments were carried out to examine the natural convective flow above square upward-facing horizontal surfaces of constant heat flux in air. Of particular interest to this study was the determination of the surface temperature as a function of the modified Rayleigh number as well as to obtain a qualitative understanding of the flow for this geometry.

The results indicated that the flow was unsteady but laminar over the range of modified Rayleigh numbers tested. The correlations obtained indicated that the Nusselt number varied with the 1/5 power of the modified Rayleigh number as predicted by similarity solutions for the 2-dimensional case.