Free Convection Heat Transfer Across Inclined Honeycomb Panels

Abstract

Experimentally obtained Nusselt number-Rayleigh number plots are presented for free convective heat transfer across honeycomb panels, heated from below, and inclined with respect to the horizontal at angles of 0, 30, 45, 60, and 90 deg. Aspect ratios of honeycomb cells of 2, 3, 4, and 5 are included; the fluid contained in the cells is air. Substantial suppression of free convection is observed when compared with an air layer of the same depth but not containing a honeycomb. Heat transfer associated with the base flow is found to be of only moderate importance at angles near horizontal, but of considerable consequence for angles near the vertical. The honeycomb walls used were partly transparent to thermal radiation, and a strong radiative coupling is indicated. A correlation equation for the Nusselt number, valid over part of the experimental range, is presented.