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ISSN Online: 2377-424X

ISBN Print: 0-89116-909-1

International Heat Transfer Conference 9
August, 19-24, 1990 , Jerusalem, Israel

HEAT TRANSFER DURING THE FREEZING OF UNDERCOOLED LIQUIDS DISPERSED WITHIN AN EMULSION

Get access (open in a dialog) DOI: 10.1615/IHTC9.3670
pages 45-50

Abstract

Experiments on heat tranfers inside an emulsion when the dispersed phase crystallizes or melts are presented. The crystallization and melting processes are not symmetrical because of the large undercooling induced by the smallness of the emulsion droplets sizes. The space-time evolution of the temperature inside a metallic cylinder filled with the emulsion is investigated. The dispersed phases are pure substances as water or paraffins. Upon heating, the thermodynamic equilibrium is observed for a long time, only in the axis region of the cylinder. Upon cooling, from 13°C to 36°C .following the substances, below the melting temperature, it occurs a stabilization of the temperature in the axis region during a lapse of time depending on the cooling rate, the mass fraction or the final temperature. A simplified model based on a combination of the energy equation and the nucleation theories is proposed and explains the main experimental features.