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ISSN Online: 2377-424X

ISBN Print: 0-85295-345-3

International Heat Transfer Conference 10
August, 14-18, 1994, Brighton, UK

MODIFICATION OF THE NUCLEATE BOILING HYSTERESIS IN THE POOL BOILING OF FLUOROCARBONS

Get access (open in a dialog) DOI: 10.1615/IHTC10.4620
pages 87-92

Abstract

Experiments have been conducted using an array of five horizontal platinum wires, arranged in a vertical plane, to determine the effect of the boiling wake from one wire on the heat transfer on wires located vertically above. All experiments were conducted using FC-72, a fluorocarbon manufactured by the 3M Corporation. This liquid has a saturation temperature of 56 C at atmospheric pressure and is characterized by a very low surface tension. This low surface tension can lead to the requirement of very high superheats (of the order of 35 to 40 C) to initiate boiling nucleation.
Experiments were first conducted to determine the characteristic boiling curve for each heater wire, for conditions of subcooled and saturated pool boiling for both degassed liquids and liquids with dissolved gases. Experiments were then conducted in which the lowest wire was brought into the fully nucleate boiling range and then the heat transfer behavior of wires vertically above was investigated. Specifically, the effects of the boiling wake on the natural convection regime, on the nucleation superheat, and on the heat transfer in the nucleate boiling regime were investigated for both increasing and decreasing heat flux. It was found that the boiling wake can eliminate the temperature overshoot on wires within the wake.