Direct contact heat transfer with change of phase at high pressure in a steamwater system
Abstract
An average heat transfer coefficient based on the heat content of the bubble, half the initial area, the time to collapse, and the temperature difference of subcooling were found to vary from 6,000 to 25,000 W/sq m C, for all the operating conditions of the experiments. The above values are of the same magnitude as those calculated for a rigid, three millimeter sphere moving at the average velocity of the bubble. The instantaneous heat transfer coefficients were found to decrease with time for the lower pressure levels and to increase with time for the higher pressure levels. At the highest pressure level, the behavior of the instantaneous coefficient with time was similar to that of a bubble whose shape was spherical during the entire collapse. The deviations of the instantaneous coefficients from the above mentioned averages were within plus or minus 50 percent.
 Publication:

Ph.D. Thesis
 Pub Date:
 July 1976
 Bibcode:
 1976PhDT........46B
 Keywords:

 Heat Transfer Coefficients;
 High Pressure;
 Phase Transformations;
 Pressure Gradients;
 Steam;
 Water Vapor;
 Bubbles;
 Condensing;
 Rayleigh Number;
 Vaporizing;
 Thermodynamics and Statistical Physics