Laminar heat transfer to power law fluids in tubes with variable wall heat flux (Q801745)

The present paper deals with laminar heat transfer to non-Newtonian power law fluids in circular tubes with boundary condition of variable wall heat flux. The differential equations of motion, energy and continuity governing the problem discussed have been solved numerically by means of finite-difference scheme. The results of numerical computations are presented graphically and their physical meaning is given. A special attention has been paid to the effects of temperature dependent rheological fluid properties and viscous energy dissipation on temperature, velocity and pressure-drops distributions in heated (cooled) tubes section as well as on mean Nusselt number. In some special cases a comparison with the empirical formulae encountered in literature is presented. This work is intended to be an extension of the previous paper by \textit{G. Forrest} and \textit{W. L. Wilkinson} [Trans. Inst. Chem. Eng. 52, 10 ff. (1974)] in which the boundary condition of constant wall heat flux was considered.