Experimental study of heat transfer by natural convection in a closed cavity: application in a domestic refrigerator

Abstract

An experiment was carried out using a refrigerator model in which heat is transferred by natural convection between a cold vertical wall and the other walls, which are exposed to heat losses. The air temperature profile in the boundary layers and in the central zone of the empty refrigerator model was investigated. Temperature stratification in the vertical direction was observed with the cold zone at the bottom and warm zone at the top of the cavity. The effects of temperature and the surface area of the cold wall were studied.In order to study the effect of obstacles on temperature profiles, the refrigerator model was filled with 4 blocks of hollow spheres. Temperature profiles in this case were compared with the results with no blocks. The air temperature is lower almost everywhere in the model containing blocks. The presence of the blocks seems to enhance heat transfer particularly near the cold wall.

Interaction Effects Between Surface Radiation and Double-Diffusive Turbulent Natural Convection in an Enclosed Cavity Filled With Solid Obstacles

“…In the last decade or so the trend in buoyancy driven flow research has shifted to the examination of cavity flow coupled with heat and mass transfer [Laguerre et al 2005, McBrain 1997and Weaver and Viskanta 1991. Most of the studies in this category are concentrated on steady state laminar flow of Rayleigh number ranging from 10⁴ to 10⁶ [Desrayaud and Lauriat 2001, Hammou et al 2004and Laaroussi and Lauriat 2008.…”

“…Temperature Driven Buoyancy Flow in Cavity Buoyancy driven flow inside cavities has been the subject of extensive research for the last two decades due to the growing demand for detailed quantitative knowledge of the transfer processes and also due to its relevance in many practical applications [Kadem et al 2011 andLaguerre et al 2005]. The basic set up for such flows, which has also attracted most attention from researchers, is a rectangular cavity whose vertical walls are heated differentially [Barakos and Mitsoulis 1994, Calcagni et Mixture (air and water vapour) p product the fact that such a rig is relatively easy to fabricate, detailed data on the flow, turbulence and heat transfer have been collected through experiments [Ampofo and Karayiannis 2003, Dafa' Alla and Betts 1996, Penot et al 2010.…”

Heat Transfer and Air Flow in a Domestic Refrigerator

“…• It was observed by experiment and by numerical simulation that the heat transfer and airflow in domestic refrigerator are 3D. 45,46 To study this more complex 3D configuration, numerical simulation is presented in the next section.…”

“…In our previous study, it was found that the thickness of the boundary layer was less than 2 cm. 45 In addition to the overall thermal stratification in the cavity, stratification is also observed in each gap between two shelves or between a shelf and a product. It is to be emphasized that for the refrigerator loaded with the "test product," the symmetry plane is located in the gap between two piles.…”

Natural convection and flow simulation in differentially heated isosceles triangular enclosures filled with porous medium

“…In fact, buoyancy-driven convection in a closed cavity with differentially heated isothermal walls is a prototype of many industrial applications and in particular, triangular enclosure has received considerable attention because of its applicability in various fields such as • Design of industrial equipments such as catalytic reactors, heat exchangers, crude oil production, cooling of electronic devices such as PC, TV, nuclear waste management, etc. (Incropera, 1988;Sharif and Mohammad, 2005;Laguerre et al, 2005.) • Energy related applications, for example: thermal insulation of building using air gaps, solar energy collectors, furnaces and fire control in building, etc.…”