Correlation Equations for Natural Convective Heat Transfer From Two Inclined Vertically Spaced Narrow Isothermal Flat Plates

Abstract

Natural convective flow over narrow plates induces an inward flow near the edges of the plate causing the flow to be three-dimensional near the edges of the plate. This influences the heat transfer rate near the edges of the plate and is referred to as the edge effect. The primary objective of this paper is to numerically study this edge effect and the interaction of the flows over two inclined vertically separated narrow heated plates of the same size embedded in a plane adiabatic surface. The cases where the plates and surrounding adiabatic surface are inclined at positive or negative angles to the vertical have been considered. Results were obtained by numerically solving the full three-dimensional form of governing equations using the commercial finite volume based software Fluent©. Results have only been obtained for a Prandtl number of 0.7; this being the value existing in the application which involved airflow that originally motivated this study. The results presented here cover Rayleigh numbers between 103 and 107, at all values of W considered, plate width-to-height ratios between 0.2 and 1.2, gap, at all values of W considered, to the plate height ratios of between 0 and 1.5, and, at all values of W considered, angles of inclination of between −45 deg and +45 deg. The effects of the Rayleigh number, dimensionless plate width, dimensionless gap between plates, and inclination angle on the heat transfer rate have been studied in detail. Empirical correlations defining the effect of these parameters on the heat transfer rate have been derived.

Experimental and numerical studies of laminar natural convection heat transfer from an isothermally heated narrow flat plate oriented at different angles of rotation

“…These studies encompass plates oriented at various angles facing upward or downward, causing the buoyancy force to have two components over the inclined plate. Natural convection heat transfer from a wide inclined plate has been investigated by many researchers, including [21][22][23][24][25][26][27], while natural convection heat transfer from a narrow inclined flat plate has been investigated by Kalendar and Oosthuizen [28][29][30]. Oosthuizen and Kalendar [28,29] experimentally and numerically studied natural convective heat transfer from an isothermally heated inclined narrow flat plate in the laminar flow regime.…”

“…Natural convection heat transfer from a wide inclined plate has been investigated by many researchers, including [21][22][23][24][25][26][27], while natural convection heat transfer from a narrow inclined flat plate has been investigated by Kalendar and Oosthuizen [28][29][30]. Oosthuizen and Kalendar [28,29] experimentally and numerically studied natural convective heat transfer from an isothermally heated inclined narrow flat plate in the laminar flow regime. Their results showed that the mean Nusselt number increases with decreasing width of the plate and is higher for a positive inclination angle than it is for the corresponding negative inclination angle.…”