NUMERICAL-ANALYSIS OF THE THERMAL-CONVECTION FOR HERSCHEL-BULKLEY FLUIDS

This article presents a numerical analysis of the laminar forced convection in a cylindrical duct for a thermodependent Herschel-Bulkley fluid. Two boundary conditions are considered: constant wall heat flux and constant wall temperature. Both fluid flow and heat transfer are studied. The governing equations are solved using the finite difference method with an implicit scheme. It is assumed that all fluid properties other than consistency K, are constant. The K-T relation used is K = K-0 exp (- bT). The results obtained enable us to characterize completely the dynamic and thermal fields structure. For a practical use of the computed results, correlations for local Nusselt number and pressure gradient are proposed taking into account the modification of the wall shear rate induced by the theological properties and the temperature-dependent character of the fluid.