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ISSN Online: 2377-424X

International Heat Transfer Conference 12
August, 18-23, 2002, Grenoble, France

An Experimental Study on the Influence of Force Fields on CHF in Pool Boiling

Get access (open in a dialog) DOI: 10.1615/IHTC12.4540
6 pages

Abstract

Critical heat flux (CHF) in pool boiling on a wire was investigated in the presence (or less) of a cylindrical d.c. electric field (EF) and under variable gravity conditions. To this aim, an experimental facility was operated in parabolic flight, allowing data collection and acquisition of high-speed video images for gravity accelerations ranging from 0.02 gE to 1.5 gE. In the absence of EF, CHF significantly decreased in microgravity. The application of EF yielded CHF improvement, and for intense enough EF, the value of CHF in reduced gravity was coincident with the one in terrestrial gravity, thus demonstrating the dominance of electric forces on the buoyancy ones. The analysis of high-speed video images revealed the role of bubble lateral coalescence along the wire in triggering CHF occurrence in micro-g. The comparison with an existing correlation for CHF improvement in the presence of EF was successful for terrestrial data, but revealed some limits in predicting microgravity data at low values of EF.