HEAT-TRANSFER STUDIES OF HIGHLY VISCOUS NON-NEWTONIAN FLUIDS IN VERTICAL TUBES BY FINITE-ELEMENT METHOD

A numerical method capable is developed for handling steady laminar no w and heat transfer of a highly viscous power-law fluid whose density, viscosity, specific heat and thermal conductivity, vary with temperat ure. The governing equations are found to be continuity, monmentum and energy expressions. Important effects such as varying viscosity, natu ral convection and viscous dissipation are incorporated in the theoret ical model. These equations are being attracted by employing a decoupl ed finite element method. Galerkin's principle is used to handle the m omentum and continuity equations. Consistent (SU/PG) and non-consisten t (SU) streamline upwind methods are employed for the energy equation. Comparison of calculated results and experimental data shows good agr eement. Similar results are obtained with SU and SU/PG methods. Veloci ty and temperature profiles which provide insights into the process ar e also given.