ABSTRACT
Phenomena involved in non-newtonian fluids transport mainly pertain to the technologies of production and use of a great number of chemical process industries. The enclosure of the constitutive equation in the momentum equations of fluidodynamics leads to a fundamental system of equations analogous to that of Navier-Stokes for Newtonian fluids. Three categories of fluids are generally distinguished: Purely viscous fluids; Boltzmann fluid; and Viscoelastic fluids. Owing to the lack of suitable, systematic experimental data, constitutive models for tixotropic, rheopectic, and viscoelastic fluids are generally lacking. Non-newtonian fluid heat transfer research presently pertains mainly to purely viscous fluids, with data lacking on thermal properties of other fluid categories. Rheopectic fluids, on the contrary, show an increase of viscosity with the duration of the applied stress. When the stress is removed, the structure gradually reforms and the viscosity increases again. Viscoelastic fluids show a quite complex behavior, reacting to external stresses elastically and viscously.
