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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

AN INVESTIGATION OF BOILING PHENOMENA IN SUPERHEATED FREE JETS

Get access (open in a dialog) DOI: 10.1615/IHTC8.870
pages 2251-2256

Abstract

Pressurized water in a boiler is heated over 100°C and flows through circular, short nozzles of different intakes and diameters into the ambient air. Because of the nozzle design no boiling occurs on the surfaces of the nozzle but in the metastable liquid jet two other, different phenomena of boiling are recognized. By measuring the delay time in boiling, the bubble growth and the mean bubble frequencies as a function of the state of the fluid in the boiler, the condition of flow, the jet diameter, the nozzle shape and the gas content, it was possible to ascertain these phenomena theoretically as well. One of the phenomena does not depend on nozzle shape or jet velocity but only on the overexpansion of the jet. The other depends strongly on nozzle shape, diameter and condition of flow. In knowledge of the different boiling phenomena it is possible to design nozzles, which prevent boiling. These nozzles render highly superheated free jets possible, for which there are interesting uses in the technical applications.