ARTICLE:

• BOILING INCIPIENCE AND HEAT TRANSFER IN A MICROTUBE: EXPERIMENTAL MEASUREMENTS USING LIQUID CRYSTAL THERMOGRAPHY  download article

R. Muwanga
Concordia University, Canada

I. Hassan
Department of Mechanical and Industrial Engineering, Concordia University, Montreal, Quebec, Canada, H3G1M8

ABSTRACT

This paper presents experimental measurements of boiling heat transfer in a 1.067 mm inner diameter tube using liquid crystal thermography for wall temperature measurement. The study was motivated by the two-phase microchannel pumped cooling loop, a recent technology proposed for thermal management of tomorrow's high-end electronics. The working fluid was FC-72, which is a dielectric coolant. Measurements were obtained in a closed loop test facility. A unique flow boiling onset has been observed whereby a large wall temperature gradient travels along the tube. During flow boiling conditions, wall temperature fluctuations have been observed. The use of a thermographic technique has added insight into the flow boiling characteristics and acts as a partial flow visualization method. Local heat transfer coefficients are presented and compared with correlations for both macro and microchannels. The heat transfer coefficient is found to be influenced by the heat flux but only mildly by the quality at low values of quality.

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EXP-20 pages

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