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THREE-DIMENSIONAL LAMINAR AND TURBULENT NATURAL CONVECTION IN A CONTINUOUSLY/DISCRETELY WALL-HEATED ENCLOSURE CONTAINING A THERMAL LOAD

2003; Taylor & Francis; Volume: 44; Issue: 2 Linguagem: Inglês

10.1080/713838194

1521-0634

John Abraham, E. M. Sparrow,

Heat Transfer and Optimization

Abstract An experimentally motivated numerical simulation of three-dimensional natural convection in a heated enclosure containing a discrete thermal load has been performed. A special feature of the simulation is the use of the actual equation of state of air, in contradistinction to the customary Boussinesq model. Heating is accomplished continuously at all the walls of the enclosure and by a discrete, rod-like heater situated at the enclosure floor. The bulk of the solutions were carried out for steady laminar flow, but a specific solution for turbulent flow was performed for comparison purposes. By making use of an extended quasi-steady model, the steady-state results were employed to predict the time-varying temperature of the thermal load. The agreement between the numerically based predictions and the experimental data obtained by the authors was very good. For the case selected for the laminar-turbulent comparison, only modest deviations occurred for the heat transfer rates at the surfaces of the load. It was also shown that steady heat transfer rates could prevail at the load surfaces despite the fact that the flow field beneath the load was unsteady.