Non-isothermal controlled shearing rate rheometry of a yield-pseudoplastic fluid: effects of shear heating

The hydrodynamic as well as the thermal fields associated with Couette flow of a non-Newtonian yield-pseudoplastic fluid between two concentric cylinders are numerically investigated. The considered problem consists of a rotating, solid, inner cylinder in a fixed hollow outer cylinder. The outer surface of the inner cylinder is assumed to be adiabatic, while the hollow one is considered to have a constant temperature. The investigated thermal field is developed due to the viscous heating phenomenon associated with tangential flows of such high apparent viscosity fluids when subjected to intense shear. The results reveal the profound effect of the governing parameters on the temperature field and the corresponding Nusselt number distributions. The geometry as well the boundary conditions simulate the widely used controlled shearing rate concentric cylinders rheometer. While the developed hydrodynamic and thermal fields are due to a fixed outer and rotating inner cylinders, they would be identical, in the presented form, to those corresponding to a fixed inner and rotating outer cylinders.