Axial Heat Conduction Effects in Forced Convection Along a Cylinder

Abstract

An analytical study is performed to determine the effects of axial heat conduction and transverse curvature on laminar forced convective heat transfer of liquid metals along a circular cylinder. The flow and thermal boundary layers for this problem are nonsimilar, the non-similarity arising both from the transverse curvature ξ = (4/R)(νx/u∞)1/2 of the cylindrical surface and from the axial heat conduction effect expressible as Ω = 1/Pex, where Pex is the local Peclet number. The governing equations are solved by the local nonsimilarity method in which all the terms in the conservation equations are retained and only terms in the derived subsidiary equations are selectively deleted according to the levels of truncation. Numerical results are presented for liquid metals having representative Prandtl numbers of 0.03, 0.008, and 0.003 over a wide range of ξ values from 0 (i.e., a flat plate) to 4.0 and Ω values from 0 (i.e., without axial heat conduction effect) to 0.20. The results indicate that the local surface heat transfer rate increases with an increase in the transverse curvature of the cylindrical surface, an increase in Prandtl number, and an increase in the axial heat conduction parameter or a decrease in Peclet number.