Abstract:
This research presents a numerical simulation by investigating the coupled heat transfer by both conduction and free convection phenomena within a thick-walled square enclosure. This analysis compares two types of enclosures, one with an inner cavity and one without an inner cavity. The inner cavity is exposed at its top and linked to the enclosure ceiling. The presence of these internal open cavities leads to alterations in convection patterns, resulting in diminished flow and the creation of a confined fluid compartment at the enclosure core. Consequently, this arrangement lowers the local Nusselt number(Nul) along the hot wall, ultimately reducing the heat flux through the enclosure. The study delves into the impact of varying shaped internal cavity dimensions on heat movement within the enclosure, encompassing a range of Rayleigh numbers(Ra) from 103 to 106 and a wall thickness of (0.05 ≤ W ≤ 0.2). The outcomes reveal that internal cavities with shorter sides act as flow deflectors, whereas those with longer sides form compartments that facilitate new flow circulation at the enclosure base. The most pronounced impact on heat flow arises when the maximum inner square shape is present within the hollow enclosure, with the same Rayleigh number and wall thickness in the inner cavity. Under these specific conditions, the heat flux reaches its lowest point, underscoring the optimal configuration for minimizing heat transfer within the system. This analysis produces valuable insights that can inform the design and optimization of natural convection systems featuring internal cavities. This model specifically will contribute to the hollow brick design.