Entropy generation due to non-Newtonian fluid flow in annular pipe with relative rotation: constant viscosity case

Entropy generation due to Non-Newtonian fluid flow in an annular pipe with relative rotation is investigated. A third grade fluid with constant viscosity is accommodated in the analysis. Relative rotational motion is present between inner and outer cylinders, which induces the flow. Analytical solutions for velocity and temperature distributions are presented, and entropy generation number is computed for different dimensionless values of non-Newtonian viscosity, Brinkman's number and velocity ratio. It is found that the increasing of dimensionless non-Newtonian viscosity lowers the number entropy generation. This is more pronounced in the region close to the annular pipe inner wall. The increasing of Brinkman's number enhances the number entropy generation, particularly in the vicinity of the annular pipe inner wall.