Heatline based thermal management for natural convection within right-angled porous triangular enclosures with various thermal conditions of walls

Analysis of natural convection in porous triangles have many important energy related applications in geophysical and solar energy fields. A numerical study on heat distribution and thermal mixing during steady laminar natural convective flow inside a right-angled triangular enclosure filled with porous media subjected to various wall boundary conditions is investigated in this study using Bejan’s heatlines approach. Influence of various thermal boundary conditions and inclination angles (φφ) on evaluation of complex heat flow patterns are studied as a function of Darcy numbers (Da) for various regimes of Prandtl (Pr) and Rayleigh (Ra)   numbers. Studies illustrate that maximum heat transfer occurs at the top vertex for lower top angle (φ=15∘)(φ=15∘) at higher Da  (Da=10−3)(Da=10−3). As φφ increases to 45∘45∘, the maximum heat flux at the top vertex decreases and thermal mixing increases irrespective of Da and Pr. The enhanced convection at higher Da   significantly affects the heat flow distribution, which is clearly depicted by high local Nusselt numbers at Da=10−3Da=10−3. It is also found that isothermal heating of walls enhances the heat distribution and thermal mixing. Overall, it is shown that heatlines provide suitable guideline on thermal management in porous right-angled triangular enclosures with various heating strategies.

► Analysis on heatlines is carried out for various isothermal and nonisothermal heating situations.
► Natural convection for fluids within porous right-angled triangular cavities are considered.
► Detailed analysis on flow, temperature and heatline characteristics has been done.
► Optimal thermal mixing and enhanced heating rates are compared for various angles of inclination.
► Effects of Darcy number and Prandtl numbers are also investigated.