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ISSN Online: 2377-424X

International Heat Transfer Conference 3
August, 7-12, 1966, Chicago, USA

FUNDAMENTAL ASPECTS OF SUBCOOLED BOILING WlTH AND WITHOUT DISSOLVED GASSES

Get access (open in a dialog) DOI: 10.1615/IHTC3.1110
pages 1-11

Sinopsis

I - The effects of dissolved gas in subcooled boiling (degassing and vaporization) are experimentally studied in different conditions : air saturated water in free and forced convection with visual observation of the heat exchange mechanisms (photography and Schlieren high speed cinematography), stagnant metaterphenyl at 350°C, pressure less than 4kg/cm2, gas content between 0 and 26cm3/100g, terphenyl in forced convection at 350-400°C, 5 to 9kg/cm2 pressure, 4 to 10 meters per second convection velocity, and 10 to 70cm3/100 gas content. Degassing improves the heat exchange without increasing the pressure drop as long as the wall temperature is lower than the saturation one of the degassed liquid.
II - In subcooled boiling of degassed water, histograms of bubble dimensions are obtained by a photographic method. They can be considered as the superposition of two distribution curves : the first one corresponds to isolated bubbles, the second one to agglomerated bubbles. Heat exchange mechanisms observed by Schlieren method are briefly recalled.