COMPUTER MODELING OF TRANSIENT THERMAL-FLOWS OF NON-NEWTONIAN FLUIDS

In this report two axisymmetric transient thermal non-Newtonian fluid problems are studied. The first is a capillary flow model problem for a thermal power-law fluid and Graetz number up to 60, governed by a derivative temperature boundary condition. The second is a glass oven flow problem for thermal, Newtonian and power-law fluids, flowing in a complex shaped domain driven by a gravitational body force for thermal Peclet numbers up to 100. The flow domain in this case is a straight pipe with a constriction formed from an axisymmetric angled obstruction on the wall. The results obtained for these problems provide good agreement with both experimental and numerical results supplied by industrial collaborators. Of particular concern here is the nature of the transient development of the flows involved under varying material properties. To this end the code has been validated under typical industrial conditions and found to be robust up to Peclet numbers of at least 100, and involving up to 1000 degrees of freedom.