Computational study on the effects of variable viscosity of micropolar liquids on heat transfer in a channel

Abstract

A numerical model is developed to study the effects of temperature-dependent viscosity on heat transfer in magnetohydrodynamic flow of micropolar fluid in a channel with stretching walls. The governing equations for linear and angular momenta and energy are transformed to a set of nonlinear ordinary differential equations by using similarity variables, and resulting problems are solved numerically by quasi-linearization. The effects of the various physical parameters on velocity, microrotation and temperature profiles are presented graphically and numerically. Finally, the effects of pertinent parameters on local skin-friction coefficient and local Nusselt number are also presented graphically. Some important observations regarding the effect of vortex viscosity parameter, microinertia density parameter, spin gradient viscosity parameter and couple stress on flow fields are noted and displayed. Numerical values of shear stress, couple stress and heat flux are computed and tabulated. The viscosity variation parameter enhances the shear stress and the couple stress. However, the heat transfer exhibits an opposite trend. The viscosity parameter is the most influential on thermal distribution. The magnetic field acts as a retarding force which reduces the normal and streamwise velocities as well as the microrotation distribution