Homotopy perturbation solution for flow of a third-grade fluid in helical screw rheometer

This paper provides a theoretical study of steady flow of an incompressible third grade fluid in helical screw rheometer. The model developed in cylindrical coordinates pertains to second order nonlinear coupled differential equations that are solved using homotopy perturbation method. Expressions for velocity components in θ and z-direction are obtained. The volume flow rates are calculated for the azimuthal and axial components of velocity profiles by introducing the effect of flights. The results have been discussed with the help of graphs. It is noticed that extrusion process depends on the involved non-Newtonian parameter and pressure gradients.