Mixed convective transport in Maxwell hybrid nano-fluid under generalized Fourier and Fick laws

Abstract

Generalized laws of Fourier and Fick based on thermal and solutal relaxation times are used in the development of the system of PDEs related to simultaneous transport of heat and species in Maxwell fluid with mono and hybrid nano particles. The developed systems of PDEs are solved numerically by using the finite element method (FEM). Implementation of the FEM algorithm is discussed. The parametric study is carried out by performing various theoretical and numerical experiments. Related outcomes are presented in the form of graphs and numerical data. Convergence is ensured and grid-independent solutions are derived. Thermal relaxation parameter tends to lower down the temperature of the fluid and thermal boundary layer becomes shorter for higher values of thermal relaxation parameter. Concentration relaxation parameter has shown a decreasing impact on the diffusion of species in Maxwell fluid. Deborah number has reduced the diffusion of momentum in Maxwell fluid. Convective transport of both heat and species is compromised when Deborah's number is increased. It is also noticed from simulations that Deborah number for mono nano-Maxwell fluid has greater value relative to that for hybrid nano-Maxwell fluid. The simulations have also confirmed that the effective thermal conductivity of the Maxwell fluid due to the simultaneous dispersion of copper and aluminium oxide is greater than the thermal conductivity of pure Maxwell fluid and mono nano-Maxwell fluid. Therefore, simultaneous dispersion of copper and aluminium oxide for optimized heat transfer. Thermal and concentration relaxation memory effects are responsible for reducing thermal and concentration boundary layer thickness respectively. It is also noted that heat transport rate in hybrid nano-Maxwell fluid is greater than that in mono nano-Maxwell fluid and pure Maxwell fluid. Thermal memory effects play significant role in increasing the wall heat flux.