Predictions of pressure drop and heat transfer in concentric annular ducts with modified power law fluids

The following numerical analysis examines the pressure drop and heat transfer characteristics associated with flows of modified power law fluids through concentric annular ducts. The flows considered are steady, fully developed and laminar with constant properties, except for viscosity. The boundary conditions for the heat transfer problem are constant heat flux at the inner tube, and an adiabatic outer tube. Results are presented for the friction factor-Reynolds number product and for the Nusselt number as a function of a dimensionless shear rate parameter. These are expressed as correlation equations which give a convenient description of the results throughout the complete domain of the analysis: from low shear rates where the viscosity is Newtonian, to the higher shear rates where the behavior is purely power law, and at the intermediate shear rates where the viscosity is transitional.