Mixed Convection in Horizontal Internally Finned Semicircular Ducts

Abstract

The problem of combined free and forced convection in horizontal semicircular ducts (flat wall at the bottom) with radial internal fins is investigated from a numerical point of view. The wall of the duct is assumed to have a uniform heat input along the axial direction with a uniform peripheral wall temperature (H1). The analysis focuses on the case of hydrodynamically and thermally fully-developed laminar flow. The governing equations for the velocity and temperature are solved by using a control-volume-based finite-difference approach. The fluid flow and heat transfer characteristics are found to be dependent on the Grashof number, the fin length and the number of fins. It is also found that the heat transfer rate increases with the Grashof number and is more intense with respect to the case of finless semicircular ducts. The most remarkable outcome of the present study is that, for each number of fins an optimum fin length exists at which the Nusselt number attains a maximum. Keyword: Laminar Mixed Convection, Semicircular Ducts.