| Abstract: | Laminar friction loss and heat transfer characteristics for a non-Newtonian fluid described by a general viscosity function of the structural type have been computed for tube and slit geometries. The model includes most other models for fluids without a yield stress as special cases. The Graetz problem for constant wall temperature and temperature independent properties has been solved, including viscous dissipation, for the transverse and axial temperature distribution. Both momentum and energy transport characteristics are shown to be strongly dependent upon a dimensionless fluid time constant, which characterizes the transition from Newtonian to non-Newtonian shear thinning behavior. A direct and exact analogy between the momentum and energy transport mechanisms is demonstrated for hydrodynamically and thermally fully developed flow, provided the heat transfer rate is represented by a suitably defined Nusselt number. |
