Computational study of magneto-convective flow of aqueous-Fe3O4 nanoliquid in a tilted cylindrical chamber partially layered by porous medium: Entropy generation analysis

Abstract

In various industrial applications, the main objective is to enhance thermal efficiency by minimizing the generation of entropy. Specifically, achieving optimal thermal efficiency in a tilted cylindrical chamber poses significant challenges due to the combined effects of tangential and normal gravity components. Our study focuses on the flow dynamics, thermal transport, and entropy generation of Fe3O4/H2O nanoliquid within a cylindrical annular enclosure by incorporating the synergistic effects of magnetic force, geometric inclination angle, and thickness of the porous region. The Brinkman-Forchheimer-extended Darcy model for ferrofluid motion and the one-equation model for heat transfer are applied in the porous region, while the conventional Navier-Stokes and energy equations are used in the fluid-only region. A series of computations is performed for various key parameters, such as Hartmann number ( 0 <= Da <= 60), Darcy number ( 10(-5)<= Ha <= 10(-1)), porous layer thickness ( 0.1 <=epsilon <= 0.9), and angle of inclination ( -60 degrees <=gamma <= 60 degrees). Our results reveal that the heat transport rate is enhanced by 48.6% with an increase in the Darcy number from 10(-5) to 10(-1). Moreover, the flow circulation and heat transport can be optimized by tilting the enclosure anticlockwise. It has been found that 91.8% of flow strength can be enhanced by rotating the enclosure from -60 degrees to 60 degrees. Finally, this study suggests that the inclination angle of 30 degrees and a porous layer thickness of 0.3 emerge as the ideal configuration to obtain optimal performance, particularly for lower Hartmann and higher Darcy numbers. Our findings will provide insight into optimizing thermal processes in nanoliquid-filled enclosures subjected to magnetic force.