Thermal analysis of buoyancy-driven flow in a square enclosure filled with porous medium

Abstract

The scope of the present investigation is to explore the thermal convection in square-shaped, porous enclosures demonstrating the impact of cavity orientation. The differential equations controlling the fluid flow and energy transfer are solved using the finite volume framework. The Darcy-Brinkman-Forchheimer model is selected for porous medium. The investigation is executed for modified Rayleigh number (Ram) from 102 to 104. The orientation of the enclosure is varied from the horizontal position (γ = 0°) to the vertical position (γ = 90°) at an interval of 15°. The flow pattern and the heat transfer are examined using the traditional method of streamlines and isotherms. The Nusselt number (Num) is employed to measure the transport of energy by thermal convection. The results indicate that the Num varies with the change in the Ram and cavity orientation. When the cavity is rotated from the horizontal position to the vertical position, the thermal convection increases up to a critical inclination angle (γc). However, the heat transfer by convection declines beyond the critical inclination angles. It is noted that the critical inclination angle varies with the change in the Ram. The enhancement in energy transport by convection varies with Ram. The augmentation in thermal convection is measured by the heat transfer enhancement parameter (ξ). The augmentation in energy transport is maximum for lower Ram = 102 (ξ = 34.9 %) and minimum for higher Ram = 104 (ξ = 24.3 %). This investigation helps in designing a thermal system that results in the optimum utilization of energy resources.