Natural-Convection Heat Transfer in Channels with Isothermally Heated Convex Surfaces

Abstract

This article reports on a numerical investigation conducted to study laminar natural-convection heat transfer in channels with convex surfaces that are isothermally heated. Six Grashof number (Gr) values (10 ≤ Gr ≤ 104) and 11 radii of curvature (1 ≤ κ ≤ ∞) are considered. The results are displayed in terms of streamline and isotherm plots, centerline pressure profiles, inlet mass flow rates, and local and average Nusselt number estimates. At the lowest radius of curvature (κ = 1), computations reveal the formation of recirculation zones in the exit section for all values of Grashof number considered. As the radius of curvature increases, the Gr value at which recirculation occurs also increases, until it disappears at κ values greater than 1.5. For all configurations studied, the average Nusselt number results indicate an increase in heat transfer with increasing Grashof number values. Moreover, the value of κ at which peaks increases with increasing Gr. Inlet volume flow rate and average Nusselt number correlations are presented.