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A two dimensional model of the transient natural convection in a freezer is studied numerically by finitevolume approach. The temperatures of the freezer outside surfaces and the evaporator vary in specifiedmanners, which were taken from an experimental work. The fluid in the freezer is of the Bousinnesqtype and the flow is assumed laminar. The transient heat conduction in the insulating layers and thetemperature and velocity fields of the fluid are solved conjugately. The radiation heat transfer betweenthe freezer inner surfaces is taken into account by using the additional source term method. The distributionsof the local Nusselt number along the upper and lower surfaces of the evaporator and theiraverage values in the period of periodically unsteady operation are calculated. Comparisons are madebetween the results with and without consideration of inner surface radiative heat transfer. It is foundthat the radiative heat transfer between the inner surfaces has a profound effect on the evaporator heattransfer characteristics.
A two dimensional model of the transient natural convection in a freezer is studied numerically by finitevolume approach. The temperatures of the freezer outside surfaces and the evaporator vary in specified manners, which were taken from an experimental work. The fluid in the freezer is of the Bousinnesqtype The transient heat conduction in the insulating layers and thetemperature and velocity fields of the fluid are solved conjugately. The radiation heat transfer betweenthe freezer inner surfaces is taken into account by using the additional source term method. The distributions of the the local Nusselt number along the upper and lower surfaces of the evaporator and theiraverage values in the period of cycle unsteady operation are calculated. Comparisons are madebetween the results with and without consideration of inner surface radiative heat transfer. It is found that the radiative heat transfer between the inner surfaces has a profound effect on th e evaporator heattransfer characteristics.