Two- and three-dimensional simulation of combined natural convection cooling of a drink can

Natural convection cooling of the fluid in a drink can placed in a refrigerator is investigated. In this study the full combined boundary layer system on the can wall is simulated. The cylindrical can filled with water (Pr = 7.0) at non-dimensional temperature of 0 is located within a larger cylindrical container filled with air (Pr = 0.7) at non-dimensional temperature of -1, with Raw=4.62×10 ⁸ in the water domain and Ra _a=4. 20×10 ⁶ in the air domain. The container and can have a height-width ratio A of 2 and 4. The heat capacity in the walls is neglected as the walls of the can are very thin, and hence, the assumption of zero thermal resistance at the walls is used. Initially both fluids are at rest and the temperature of the water is higher than that of the air. The study examines the placement of the inner can in two configurations. The first case has the inner can placed vertically in the middle of the outer container and the second case has the inner can placed vertically at the bottom and in contact with the outer container. The commercial package FLUENT 6.3.26 is used to investigate the behaviour of the natural convection cooling using both an axisymmetric two-dimensional mode and a non-axisymmetric three-dimensional models. The results show that the flow behaviour in the two and three dimensional models is consistent, although the plume in the air flow on top of the can was observed to be non-axisymmetric and flapping in the three dimensional models. This effect was observed to increase when the gap between the top of the can and the ceiling of the container increases. The three dimensional models have a rate of cooling around 3% slower than the corresponding two dimensional models. In general though, the two dimensional models produced satisfactory results, while requiring a lot less computational time compared to the three dimensional models.