Effect of Aspect Ratios and Sinusoidal Temperature on Heat Exchange Inside Cavity Filled with Hybrid Nanofluids

Abstract

A mathematical study was conducted for the mixed convection inside a cavity for three aspect ratios filled with hybrid nanofluids by moving the vertical walls down, where the upper wall was thermally isolated, and the two vertical walls with a temperature that is less than the lowest wall’s, which was at a sinusoidal temperature. The investigation and discussion focused on the Richardson numbers (0.1–100), hybrid nanoparticle sizes (0.0–0.08), and the impact of size on the thermal and hydrodynamic properties of hybrid nanoparticles. At lower Richardson numbers, hybrid nanoparticle volume fraction impacts the thermal behaviour model. Besides, it was observed that decreasing the effect of average Nusselt number and nanoparticle size was due to the increase in Richardson numbers.The present results also showed the vital role that sinusoidal temperature has on heat transfer.

Obstacle's effects and their location inside the square cavity on the thermal performance of Cu–Al2O3/H2O hybrid nanofluid

“…The continuity equation is written as follows 47 : $$$\frac{\partial u}{\partial x}+\frac{\partial v}{\partial y}=0.$$$…”

“…The dimensionless equations have the form 47 : $$$\frac{\partial U}{\partial X}+\frac{\partial V}{\partial Y}=0,$$$ $$$U\frac{\partial U}{\partial X}+V\frac{\partial U}{\partial Y}=\phantom{\rule{}{0ex}}-\frac{\partial P}{\partial X}+\frac{{\mu }_{{hnf}}}{{{\rho }_{{hnf}}\alpha }_{f}}\left(\frac{{\partial }^{2}U}{\partial {X}^{2}}+\frac{{\partial }^{2}U}{{\partial Y}^{2}}\right),$$$ $$$U\frac{\partial V}{\partial X}+V\frac{\partial V}{\partial Y}=-\frac{\partial P}{\partial X}+\frac{{\mu }_{{hnf}}}{{{\rho }_{{hnf}}\alpha }_{f}}\left(\frac{{\partial }^{2}V}{\partial {X}^{2}}+\frac{{\partial }^{2}V}{{\partial Y}^{2}}\right)+\phantom{\rule{}{0ex}}{(\rho \beta )}_{{hnf}}\frac{1}{{{\rho }_{{hnf}}\beta }_{f}}{Ra}\text{Pr}\theta .$$$…”