Numerical simulation for heat and mass transport of non-Newtonian Carreau rheological nanofluids through convergent/divergent channels

Recent studies on fluid flows have shown that the non-Newtonian fluid flows through convergent/divergent channels with heat and mass transport analysis of nanofluids has triggered many researchers because of their occurrence in biomedicine, cavity flow model, flow through canals, and cold drawing operations. Moreover, heat enhancement during fluid flow plays an important role in different engineering applications, which can be achieved by improving fluid thermal physical properties. Therefore, the present study aims at providing a novel mathematical model for non-Newtonian Carreau rheological fluid flow through convergent/divergent channels by employing Buongiorno's nanofluids model. The governing system of partial differential equations for Carreau fluid flow is formulated via basic conservation laws, for the first time in literature. The dimensionless variables are introduced to get the non-dimensional forms of the governing equations. The resultant system of ordinary differential equtions (ODEs) is numerical integrated using Runge-Kutta Fehlberg method with shooting technique, which is an efficient numerical technique to determine the numerical solutions of ODEs. The varying patterns of non-dimensional velocities, temperature, and concentration fields along with skin-friction, Nesselt and Sherwood numbers are simulated for various eminent physical parameters with converging and diverging walls. The underlying flow physics and thermal behavior are explored in terms of pertinent parameters, for instance, Reynolds number, channel angle, Prandtl number, Brownian motion parameter and thermophoresis parameter. From the present numerical simulations, we have concluded that the Reynolds number has an opposite effect on dimensionless velocity for convergent and divergent channels. It is recognized that the fluid velocity increases with higher values of Weissenberg number for convergent channel. Moreover, the temperature distributions enhance for larger Brownian motion parameter.