Local Thermal Nonequilibrium Analysis of Boundary Layer Flow of Carreau Fluid Over a Wedge in a Porous Medium

This work examines the steady two-dimensional mixed convection boundary layer flow of non-Newtonian Carreau fluid embedded in a porous medium. The impermeable wedge is at rest over which the momentum and thermal boundary layers form due to the motion of Carreau fluid with a large Reynolds number. We consider local thermal nonequilibrium for which the temperature of the solid porous medium is different from that of the fluid phase, and hence, a single heat-transport equation is replaced by a two-temperature model. The governed equations for flow and heat transfer are converted into a system of ordinary differential equations using a similarity approach. It is observed that local thermal nonequilibrium effects are dominant for small interphase heat transfer rate and porosity scaled conductivity parameters. It is shown that the temperature at any location of the solid porous medium is always higher than that of the fluid phase. When these parameters are increased gradually, the local thermal equilibrium phase is recovered at which the temperatures of the fluid and solid are identical at each pore. A similar trend is noticed for both shear-thinning and shear-thickening fluids. The results further show that heat exchange between the fluid and solid porous medium is similar to both assisted and opposed flows and Carreau fluid. The velocity and temperature fields for the various increasing fluid index, Grashof number, and permeability show that the thickness of the momentum and thermal boundary layer is thinner.