Investigation of entropy genaration for non-Newtonyen fluid flow in annular pipe using different viskosity models

In this study, non-Newtonian fluid flow in annular pipe, heat transfer and entropy generation have been investigated. Momentum and energy equations that belong to third grade fluids for cylindrical coordinate are derived. By using the general equations gained for cylindrical coordinate, momentum and energy equations for one dimension flow in pipe have been derived. For the derived equations the boundary conditions explaining flow in annular pipe are determined. These equations and boundary conditions have been made dimensionless to be able to generalize the results. Finally, ordinary differential equations systems that refer the one dimension flow in cylindrical coordinate are obtained. The approximate analytical solutions of these equations are investigated. Perturbation method, a pedestrian approach, is used in solving the equations. It is assumed that viscosity is changed according to the heat. The equations? analytical solutions are done by Reynold and Vogel viscosity models. Entropy analysis is used in two stages. The first stage consists of production of entropy caused by friction, and the second stage consists of production of entropy caused by heat transfer. The differences between entropy generation in Newtonian fluids and non-Newtonian fluids are shown with graphics.