Coupled energy and mass transport for non-Newtonian nanofluid flow through non-parallel vertical enclosure

Several phenomena that occur in nature and engineering are expressed mathematically in large part by nonlinear differential equations. Therefore, heat and mass transport for buoyancy driven nanofluid flow through converging/diverging channel are modelled using non-Newtonian constitutive model in form of non-linear differential equations. It is worth mentioning that such models are frequently involved in blood flow through arteries and flow through nozzles, etc. Utilizing non-dimensionless transformations, leading partial differential equations are converted to a system of nonlinear ordinary differential equations. The Runge-Kutta Fehlberg algorithm with shooting technique is exercised to tackle reduced system numerically. The computed results for dimensionless velocity, temperature, nanoparticle concentration, skin-friction coefficient, local Nusselt and Sherwood numbers are presented for both buoyancy-assisting and opposing flow. Detailed analysis revealed that temperature field is higher at opening of flow in converging channel. Furthermore, with growing buoyancy force, the skin friction coefficient decreases while local Nusselt number increases.