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Forced convection film boiling of subcooled water around a sphere

Citation

Jacobson, Richard Norman (1970) Forced convection film boiling of subcooled water around a sphere. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/0Z9T-2181. https://resolver.caltech.edu/CaltechTHESIS:08072015-152422673

Abstract

An experimental investigation was made of forced convection film boiling of subcooled water around a sphere at atmospheric pressure. The water was sufficiently cool that the vapor condensed before leaving the film with the result that no vapor bubbles left the film. The experimental runs were made using inductively heated spheres at temperatures above 740°C. and using inlet water temperatures between 15°C. and 27°C. The spheres used had diameters of 1/2 inch, 9/16 inch, and 3/8 inch and were supported by the liquid flow. Reynolds numbers between 60 and 700 were used.

Analysis of the collected non-condensables indicated that oxygen and nitrogen dissolved in the water accumulated within the vapor film and that hetrogeneous chemical reactions occurred at the sphere surface. An iron-steam reaction resulted in more than 20% by volume hydrogen in the film at wall temperatures above 900°C. At temperatures near 1100°C. more than 80% by volume of the film was composed of hydrogen. It was found that gold plating of the sphere could eliminate this reaction.

Material and energy balances were used to derive equations which may be used to predict the overall average heat transfer coefficients for subcooled film boiling around a sphere. These equations include the effect of dissolved gases in the water. Equations also were derived which may be used to predict the composition of the film for cases in which an equilibrium exists between the dissolved gases and the gases in the film.

The derived equations were compared to the experimental results. It was found that a correlation existed between the Nusselt number for heat transfer from the vapor-liquid interface into the liquid and the Reynolds number, liquid Prandtl number product. In addition, it was found that the percentage of dissolved oxygen removed during the film boiling could be predicted to within 10%.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:Chemical Engineering
Degree Grantor:California Institute of Technology
Division:Chemistry and Chemical Engineering
Major Option:Chemical Engineering
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Shair, Fredrick H.
Thesis Committee:
  • Unknown, Unknown
Defense Date:11 May 1970
Funders:
Funding AgencyGrant Number
CaltechUNSPECIFIED
NSFUNSPECIFIED
State of CaliforniaUNSPECIFIED
Standard Oil of CaliforniaUNSPECIFIED
Record Number:CaltechTHESIS:08072015-152422673
Persistent URL:https://resolver.caltech.edu/CaltechTHESIS:08072015-152422673
DOI:10.7907/0Z9T-2181
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:9088
Collection:CaltechTHESIS
Deposited By: Benjamin Perez
Deposited On:07 Aug 2015 23:13
Last Modified:21 Dec 2019 04:22

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