Influence of Viscosity and Thermal Conductivity in Boger Nanofluid Flow through Porous Disk: Finite Difference Analysis

Abstract

A constructed design-based model is employed to analyze the multiple enhancements in viscosity and thermal conductivity within a porous disk filled with Ag-water nanofluid. For the first time, we are applying the concept of utilizing diverse thermophysical properties, including viscosity and thermal conductivity impediments, to analyze entropy generation within a system. The energy equation incorporates a binary chemical reaction and Arrhenius activation energy. We utilize a system of nonlinear partial differential equations to establish the mathematical framework governing the flow. This is subsequently transformed into a nondimensional partial differential form via dimensionless variables. Numerical investigations employ a finite difference scheme, exploring diverse values of the related physical parameters. A finite difference scheme implemented in MATLAB is used to obtain numerical and graphical results, highlighting the impact of various parameters on the 2D and 3D profiles of velocity, temperature, concentration, entropy generation, skin friction coefficient, and Nusselt number for different non-dimensional parameters. The obtained output shows that boosting the values solvent fraction factor \((\beta _1)\) and relaxation time ratio \((\beta _2)\) enhances the velocity profile of NS&LVPC nanofluid in momentum boundary layer thickness on both porous disk, outperforming S&EVPC and NS&VPC configurations. Raising the temperature difference (\(\gamma _{*}\)) and activation energy (E) reduces the heat and mass transfer in the nanofluid flow over a lower porous disk. Higher values of Eckert number (Ec), magnetic parameters (M), thermal radiation (Rd), and concentration ratio parameter \((T_\text{c})\) result in increased entropy generation profiles in both porous disks. As the volume fraction increases, the heat transfer rate exhibits an inverse trend in the Nusselt number for both porous disks. However, the nanolayer thermal conductivity \((Nu_3)\) performs much better than spherical \((Nu_1)\) and non-spherical thermal conductivity \((Nu_2)\). Our findings indicate that flow performance is significantly better with nanolayer thermal conductivity and low viscosity particle concentration (NS&LVPC) compared to spherical thermal conductivity with effective viscosity particle concentration (S&EVPC) and nonspherical thermal conductivity with low viscosity particle concentration (NS&VPC).