Laminar flow and heat transfer of non-Newtonian falling liquid film on a horizontal tube with variable surface heat flux

An analysis is performed to study the laminar flow and heat transfer of non-Newtonian falling liquid film on a horizontal tube for the case of variable surface heat flux. The inertia and convection terms are taken into account. The governing boundary layer equations are solved numerically using an implicit finite difference method. Of particular interest are the effects of the mass flow rate Gamma, the concentration C of carboxymethylcellulose (CMC) solutions, the exponent m for the power-law surface heat flux, and the tube diameter D on the film thickness profiles, as well as on the local and average Nusselt numbers. It was found that an increase in the mass flow rate gamma and exponent value m increases the local and average heat transfer rates. Finally, the present simulation is found to be in good agreement with previous experimental and numerical results for Newtonian films. (C) 2001 Elsevier Science Ltd.