THE MECHANISM OF HEAT TRANSFER IN NUCLEATE POOL BOILING. Technical Report No. 19

Technical Report · Thu Feb 01 04:00:00 EST 1962

OSTI ID:4792007

Han, C; Griffith, P

A criterion is developed for bubble initiation from a gasfilled cavity on a surface in contact with a superheated layer of liquid. It is found that the temperature of bubble initiation on a given surface is a function of the temperature conditions in the liquid surrounding the cavity as well as the surface properties themselves. It is also found that the delay time between bubbles is a function of the bulk liquid temperature and the wall superheat and is not constant for a given surface. By consideration of the transient conduction into a layer of liquid on the surface, a thermal layer thickness is obtained. With this thickness and a critical wall superheat relation for the cavity, a bubble growth rate is obtained. Bubble departure is considered and it is found that the Jakob and Fritz relation works as long as the true (non- equilibrium) bubble contact angle is used. The effect on the departure size of the virtual mass in the surrounding liquid is found to be negligible at one gravity. That is, at one gravity the primary effect of bubble growth velocity on bubble departure size is found to be due to contact angle changes. The initiation, growth, and departure criterions are each experimentally and individually checked. They are then used to compute the heat transfer near the knee of the boiling curve using only an experimental determination of the number of bubbles as a function of wall superheat and other known quantities. Finally the q vs. T/sub w/ - T/sub sat/ relation is computed and measured and compared. The comparison is satisfactory. (auth)

• Research Organization: Massachusetts Inst. of Tech., Cambridge. Heat Transfer Lab.
• NSA Number: NSA-16-016503
• OSTI ID: 4792007
• Report Number(s): NP-11491; DSR-7-7673
• Country of Publication: United States
• Language: English

Related Subjects

ATMOSPHERE
BOILING
BUBBLE GROWTH
BUBBLES
COMPUTERS
DIAGRAMS
ENGINEERING AND EQUIPMENT
EXPANSION
FILMS
GASES
GRAIN SIZE
GRAVITATION
HEAT TRANSFER
JACOB CORRELATION
LIQUIDS
MASS
MATHEMATICS
MEASURED VALUES
NUCLEATE BOILING
POOL BOILING
STABILITY
SUPERHEATING
SURFACE TENSION
SURFACES
TEMPERATURE
THERMODYNAMICS
THICKNESS