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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

SUPERCOOLING BY EVAPORATION OF AN EXTRA THIN FILM MAINTAINED BY MICRO DROPLET DEPOSITION

Get access (open in a dialog) DOI: 10.1615/IHTC9.3800
pages 217-222

要約

A new, novel scheme is hereby presented by which the supercooling of a. heated surface can be achieved. Supercooling is defined as the simultaneous attainment of high heat flux and low temperature of the surface to be cooled as often required in the cooling of electronic equipments. The surface is cooled by the evaporation on the outside surface of an extra thin continuous liquid film which is maintained by the continuous deposition of extremely small droplets of an optimal size determined by a selection process on the droplet transverse migration due to the dynamic interaction between the phases in a parallel turbulent mist flow. The heated surface is thus quenched to a very low temperature while at the same time a very high heat flux is attained through the mass transfer due to evaporation from the outside surface of the film, creating an order-of-magnitude heat transfer enhancement. An experiment, has! been carried out to investigate this new mode of heat transfer enhancement in which the droplet deposition is measured by the use of a special particle-sizing two-dimensional laser-Doppler anemometry technique. The significance of the size of deposited droplets on supercooling heat transfer enhancement has been investigated. An attempt has also been made to provide a theoretical explanation to the key controlling phenomenon of transverse droplet deposition on a parallel surface by the use of a newly developed two-phase dynamic-response transverse particle migratory theory for a turbulent two-phase suspension flow.