The paper discusses the effects of homogeneous-heterogeneous reactions on stagnation-point flow of a nanofluid over a stretching or shrinking sheet. The model presented describes mass transfer in copper-water and silver-water nanofluids. The governing system of equations is solved numerically, and the study shows that dual solutions exist for certain suction/injection, stretching/shrinking and magnetic parameter values. Comparison of the numerical results is made with previously published results for special cases.

The flow, heat and mass transfer characteristics of the free convection on a vertical plate with uniform and constant heat and mass fluxes in a doubly stratified micropolar fluid saturated non-Darcy porous medium are studied. The nonlinear governing equations and their associated boundary conditions are initially cast into dimensionless forms by pseudo-similarity variables. The resulting system of equations is then solved numerically using the Keller-box method. The numerical results are compared and found to be in good agreement with previously published results as special cases of the present investigation. The effects of the micropolar, Darcy, non-Darcy and stratification parameters on the dimensionless velocity, microrotation, wall temperature, wall concentration, local skin-friction coefficient and wall couple stress coefficient are presented graphically.

This paper investigates the influence of viscous dissipation and magnetic field on natural convection from a vertical plate in a non-Darcy porous medium saturated with a nanofluid. In addition, a convective boundary condition is incorporated in the nanofluid model. A nonsimilarity transformation is used to reduce the mass, momentum, thermal energy, and the nanoparticle concentration equations into a set of nonlinear partial differential equations. The obtained equations are solved numerically by an accurate implicit finite-difference method. The accuracy of the numerical results is validated by a quantitative comparison of the heat transfer rates with previously published results for a special case and the results are found to be in good agreement. The effects of magnetic field, viscous dissipation, and non-Darcy and the convection parameters on the velocity, temperature, nanoparticle volume fraction, and heat and nanoparticle mass transfer rates are illustrated graphically.

In this article, we investigate the effects of Arrhenius activation energy with binary chemical reaction and convective boundary condition on natural convective flow over vertical frustum of a cone in a Buongiorno nanofluid under the presence of thermal radiation. The zero nanoparticle flux condition is used at the surface of frustum of a cone rather than the uniform wall condition to execute physically applicable results. For this complex flow model, a suitable non-similarity transformations are used initially and then Bivariate pseudo-spectral local linearisation method is used to solve the non-similar, coupled partial differential equations. Further, the convergence test and error analysis are conducted to verify the accuracy of numerical method. The effects of flow influenced parameters on the non-dimensional velocity, temperature, nanoparticle volume fraction and regular concentration profiles as well as on the skin friction, heat transfer rate, nanoparticle and regular mass transfer rates are analyzed.

The significance of the Soret effect on the boundary-layer stagnation-point flow past a stretching/shrinking sheet in a nanofluid-saturated non-Darcy porous medium is investigated in this study. The nanofluid-saturated porous medium is considered by incorporating the Brownian motion and thermophoresis effects. A similarity transformation is used to reduce the governing fluid flow equations into a set of differential equations and then solved numerically by an accurate implicit finite-difference method. The flow; temperature; concentration and nanoparticle concentration fields; skin friction coefficient; and heat, mass, and nanoparticle mass transfer rates are affected by the complex interactions among the various physical parameters involved in the analysis. These profiles are illustrated graphically in order to reveal interesting phenomena.