Cattaneo-Christov heat flux theory and thermal enhancement in hybrid nano Oldroyd-B rheological fluid in the presence of mass transfer

Abstract This article develops a system of partial differential equations (PDEs) for thermal enhancement in Oldroyd-B rheological fluid (OBF) using Cattaneo-Christov heat flux theory for simultaneous transport of heat energy and species in the presence of nanostructures (Cu, Al2O3). System of PDE characterizing thermal heat, momentum, and conservations relaxation times are modeled via conservation of momentum, energy, and species. This system of nonlinear PDEs is solved by the finite element method (FEM). Convergence and grid-independent solutions are derived which are further used for numerical simulations against parametric analysis. An increase in momentum relaxation time causes a significant declination in wall shear stress. However, the opposite trend for wall heat transfer rate and mass flux versus momentum relaxation time is noted. The impact of Prandtl number on wall heat transfer rate is similar to the impact of Schmidt number on wall mass flux.