Natural convection heat transfer in partially open enclosures containing an internal local heat source

Abstract

-A numerical study was conducted to investigate steady heat transfer and flow phenomena of natural convection of air in enclosures, with three aspect ratios (H/W = 1, 2, and 4), within which there is a local heat source on the bottom wall at three different positions, W h . This heat source occupies 1% of the total volume of the enclosure. The vertical walls in the enclosures are insulated and there is an opening on the right wall. The natural convection is influenced by the difference in temperature between the left and right walls, represented by a Rayleigh number (Ra e ), and by local heat source, represented by a Rayleigh number (Ra i ). Numerical simulations were performed for several values of the Rayleigh number ranging between 10 3 and 10 6 , while the intensity of the two effects -the difference in temperature on the vertical walls and the local heat source -was evaluated based on the Ra i /Ra e ratio in the range between 0 and 2500. The analysis proceeds by observing variations in the streamlines and isotherms with respect to the different Ra e , R ratios, aspect ratios, of the radius and positions of the local heat source. The average Nusselt numbers on the hot and cold walls are influenced by different values of the parameters R, Ra e , W h , and H/W. Results show the presence of different flow patterns in the enclosures studied. Thus, the flow and heat transfer can be controlled by external heating, and local heat source.

Investigation of heat transfer during melting of a PCM by a U-shaped heat source

“…The upper part of the chamber was left open to room atmosphere to accommodate thermal expansion of the PCM during melting. The open space at the ceiling of the chamber helped minimize the pressure buildup due to the volumetric expansion of the PCM upon melting [39]. The heat transferred through the open top prevented the heat buildup in the chamber and hence simulated the condition of a continuous heat transfer in a real thermal storage as the heat continued to transfer from the heat source towards the boundaries of the storage domain.…”

Simulation of Thermal Decomposition in an Open Cavity: Entropy Analysis

“…Specifically, open configurations have been numerically studied by several authors. Mariani and Coelho (2007) investigated the natural convection due to the temperature differences between left and right walls and an internal heat source in open enclosures. Rahman et al (2013) carried out an investigation of a two-dimensional laminar incompressible mixed convection flow in a ventilated cavity.…”

Linear Stability Analysis and CFD Simulation of Double-Layer Rayleigh-Bénard Convection

“…Even though it has been investigated for more than a century, the RB problem has been the subject of a large number of studies in recent years, involving, in particular, modifications of the classical RB system. For example, the problem of natural and mixed convection in enclosures is very important in the study of the cooling of electronic devices and thermal comfort (Fontana et al, 2015;An et al, 2013;Mariani and Coelho, 2007).…”