On the combined effects of chemical reaction and nonlinear thermal radiation on natural convection heat and mass transfer over a vertical plate

Abstract

The analysis of a laminar boundary layer flow near a vertical plate governed by highly nonlinear thermal radiation and chemical reaction is presented. The Boussinesq approximation is used to predict the nonlinear nature of density variation with temperature and concentration. The plate surface was subjected to the convective surface boundary condition. The partial differential equations relevant to the fluid flow was converted to ordinary differential equations, which were solved using the Runge–Kutta method after employing the shooting procedure. Some major findings are that the radiative heat flux increases the thermal energy within the boundary layer and thereby reduces the fluid viscosity, which gives rise to the velocity profile. At higher chemical reaction applications, the momentum and concentration boundary layer thickness become thinner, whereas thicker for thermal boundary layer. The rate at which the fluid reverses within the boundary increases with chemical reaction parameter. Moreover, the rate of mass transfer within the boundary layer is enhanced with chemical reaction parameters, but the contrary is true for heat transfer from the plate surface into the free stream region. There is an observable increase in the reversible fluid flow within the boundary layer for higher nonlinear density variation with temperature and concentration.