ISSN:
0001-1541
Keywords:
Chemistry
;
Chemical Engineering
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Process Engineering, Biotechnology, Nutrition Technology
Notes:
Experimental equipment to study the film boiling of liquid nitrogen on a porous heat source with vapor suction was developed. The electrically heated element was a 3.69 in. sintered stainless steel screen, which was also used as a resistance thermometer in conjunction with an a.c. potentiometric circuit. In preliminary work, this mode of heat transfer was unstable, but stability was achieved by placing a porous flow control element on the liquid side of the heater. It was found that the Nusselt number was a function of only the Reynolds number; the heat transfer coefficient was increased by a factor of as much as 2.5 over the heat transfer coefficient in normal film boiling; it was possible to vary independently any two of the three variables, heat flux, flow rate through the plate, and temperature difference; and the generated vapor was considerably superheated. Fluctuations in the local surface temperature were measured in film boiling from both porous and nonporous flat plates, indicating that momentary solid-liquid contacts can occur, for all practical purposes, in film boiling.
Additional Material:
9 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/aic.690110115
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