Analyzing heat transfer variations at specific locations in a cave filled with porous media, emphasizing non-equilibrium conditions

Abstract

ABSTRACT This study focuses on the analysis of conjugate natural convection heat transfer in a cavity filled with a permeable medium. It specifically considers the influence of confined thermal non-equilibrium and the presence of circular solid walls with partially active arcs. The study also explores the bifurcation of heat transfer at the interface of the permeable medium and solid walls. A finite element approach is employed to solve the governing equations for heat transfer in porous spaces, including porous matrices and solid walls, represented as partial differential equations. These equations are transformed into nondimensional forms based on boundary conditions and solved using the finite element method (FEM). The study examines local and overall heat transfer, varying nondimensional parameters, and the influence of active wall positions on flow patterns. Interestingly, the results demonstrate that the position of the active walls has a significant impact on the isotherms and streamlines contours in the permeable region, as well as the isotherms in the concrete walls. Specifically, an angle of 120 ∘ between the warm component and the radiator, both positioned vertically and facing each other, results in the maximum overall temperature transmission. Conversely, the lowest total heat transfer rate occurs when the angle between the hot element and cold radiator is 180°, indicating complete alignment. Moreover, the case (e) exhibits the lowest temperature transmission ratio for both the liquid and the concrete stages of the permeable medium. In the case of modifying of R k from 10 to 0.1, decrease in the temperature transmission by creating isolation regions that perform as thermal walls beside the dynamic fences. This research sheds light on the complex heat transfer behavior in a cavity with permeable media and highlights the crucial role of active wall positioning in shaping flow patterns and temperature distribution.