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ISSN Online: 2377-424X

ISBN Print: 0-89116-559-2

International Heat Transfer Conference 8
August, 17-22, 1986, San Francisco, USA

TRANSIENT HEAT TRANSFER IN A LIQUID SPHERE

Get access (open in a dialog) DOI: 10.1615/IHTC8.1600
pages 1889-1893

Resumo

The transient heating of drops is of particular interest to those working in the field of spray combustion and, more generally, in the chemical process and power industries. In this paper a drop with a rigid surface boundary has been modelled by filling a hollow 11.5 cm diameter thin-walled copper sphere with three different liquids. The sphere was brought to a uniform temperature approaching 0 °Ð¡ before being plunged into water boiling violently at 100 °C, thus establishing fixed boundary conditions for the transient heat transfer. Thermocouples were placed across a diameter of the sphere to record the internal temperatures. The angle of inclination of the diameter to the horizontal was increased in a succession of experiments from zero to ninety degrees, thereby enabling the changing temperature field of the vertical diametral plane to be established. As expected, the internal circulation generated through buoyancy was found to have a very significant effect on the heat transfer process such that the liquid sphere reached thermal equilibrium very much quicker than the equivalent solid sphere as deduced from theoretical considerations. The effect of buoyancy circulation is similar to that reported for the Hills vortex circulation for liquid spheres in moving gas flows and should not, as is usual, be overlooked.