Dynamics of non-Newtonian methanol conveying aluminium alloy over a rotating disc: consideration of variable nanoparticle radius and inter-particle spacing

The advancement of non-Newtonian nanofluid innovation is a crucial area of research for physicists, mathematicians, manufacturers, and materials scientists. In engineering and industries, the fluid velocity caused by rotating device and nanofluid has a lot of applications such as refrigerators, chips, heat ex-changers, hybrid mechanical motors, food development, and so on. Due to the tremendous usage of the non-Newtonian nanofluid, the originality of the current study is to explore the influence of nanoparticle radii and inter-particle spacing effects on the flow characteristics of Casson methanol-based aluminium alloy (AA7072) nanofluid through a rotating disc with Joule heating and magnetic dipole. The present problem is modeled in the form of partial differential equations (PDEs), and these PDEs are converted into ordinary differential equations with the help of suitable similarity transformations. The analytical solution to the current modeled problem has been obtained by using the homotopy analysis method (HAM) and numerical solutions are obtained by employing Runge-Kutta-Fehlberg method along with shooting technique. The main purpose of the present research work is to analyze the behavior of the velocity and temperature of the nanofluid for small and large radius of the aluminium alloy (AA7072) nanoparticles and inter-particle spacing. The radial and tangential velocities are enhanced due to rising ferro-hydrodynamic interaction parameter and the skin friction force for radial and tangential directions are enhanced 10.51% and 2.16% whenh= 0.5. Also, the heat transfer rate is reduced 18.71% and 16.70% whenh= 0.5% andRp= 1.5. In fact, the present results are compared with the published results and they met good agreement.

Marangoni convection in a hybrid nanofluid-filled cylindrical annular enclosure with sinusoidal temperature distribution

The current research numerically investigates the Marangoni convection in a cylindrical annulus filled with hybrid nanofluid saturated porous media. The interior and exterior walls are subjected to spatially varying sinusoidal thermal distributions with various amplitude ratios and phase deviations. The limits at the top and bottom are adiabatic. To solve the system of non-dimensional governing equations, the finite difference approach is applied. The main objective of the ongoing study is to investigate the impact of the Marangoni number, nanoparticle volume fraction and the radii ratio on the amplitude ratio and phase deviation. Also, the fluid flow, thermal characteristics, local and average Nusselt numbers are analysed in the hybrid nanofluid-filled vertical cylindrical annulus with magnetic effects. The findings indicate that the sinusoidal temperature promotes multicellular flow in the porous annular region. In the annulus with sinusoidal boundaries, the Marangoni number underperforms while the nanoparticle volume fraction outperforms.

Coupled Free and Forced Convection Heat Transfer in a Porous Enclosure Saturated by Nanofluid with Irregular Temperature Distributions on Sidewalls

A two dimensional steady and laminar mixed convection flow in lid-driven porous cavity filled with Cu-water nanofluid is presented in this numerical investigation. The vertical side walls are considered with two spatially varying sinusoidal temperature distributions of different amplitude ratios and phase deviations while the horizontal walls are thermally insulated. The transport equations are solved using finite volume method on a uniformly staggered grid system. The variations of fluid flow, heat transfer, mid-plane velocity, and Nusselt number were discussed over a wide range of Richardson number $(Ri)$ , Darcy number $(Da)$ , porosity $(\epsilon)$ , amplitude ratio $(\epsilon_a)$ , phase deviation $(\phi)$ , and solid volume fraction $(\chi)$ . The results show that the total heat transfer rate increases on increasing Darcy number, amplitude ratio, and solid volume fraction with fixed $Ri$ . For $\phi=\frac{3\pi}{4}$ , the average Nusselt number gets its maximum value when the natural convection dominates. It is found that for $Ri =0.01$ and $1$ , the total heat transfer rate decreases on increasing porosity whereas for $Ri=100$ it is contradictory. It is also observed that the heat transfer is affected mainly on the right side wall where the phase deviation varies from $0$ to $\pi$ . But the effect of $\phi$ is not significant on the left side wall. The sinusoidal temperature distribution along the sidewalls gives better heat transfer rate than the uniform temperature.