Flow patterns and heat transfer correlations in partially active cavity filled with water at its density maximum

Abstract

The work presents a numerical study of natural convection of water at its density maximum in a partially active square cavity, nine relatives locations of the partially heated/cooled zone are investigated as well as the effect of different thermal boundary conditions represented as the inversion parameter $\theta .$ Two behaviors of average Nusselt number ${\mathit{Nu}}_{\mathrm{ave}}$ has been detected, at $\theta >0.5$ Top–Middle, Top–Bottom, and Middle–Bottom configurations give rise to a maximum ${\mathit{Nu}}_{\mathrm{ave}},$ Conversely, at $\theta <0.5$ Middle–Top, Bottom–Top, and Bottom–Middle configurations that take precedence. A heat transfer correlation based on a geometric parameter describing the locations of the active zone and the density inversion parameter $\theta$ is proposed.