Prediction of Transient Inception of Boiling in Terms of a Heterogeneous Nucleation Theory

1981 ◽  
Vol 103 (1) ◽  
pp. 69-73 ◽  
Author(s):  
L. Nghiem ◽  
H. Merte ◽  
E. R. F. Winter ◽  
H. Beer
Keyword(s):  
Time Dependence ◽  
Heterogeneous Nucleation ◽  
Homogeneous Nucleation ◽  
Time Dependent ◽  
Nucleation Theory ◽  
Heater Surface ◽  
Power Inputs ◽  
Homogeneous Nucleation Theory ◽  
Transient Boiling

Transient boiling in water and Freon 113 with various heater surfaces was investigated experimentally with step power inputs. It was observed that the inception or onset of boiling depends not only on the temperature, but is time dependent as well. This dependence can be explained in terms of a heterogeneous nucleation theory based on the homogeneous nucleation theory. The influence of the heater surface was accounted for by a nucleation factor which is liquid-specific. With this factor and one experimental value of inception for a given system, the time dependence of inception temperature can be computed.

Comments on Homogeneous Nucleation Theory

1971 ◽  
Vol 42 (10) ◽  
pp. 3900-3903 ◽  
Author(s):  
Kazumi Nishioka ◽  
G. M. Pound ◽  
Jens Lothe ◽  
J. P. Hirth
Keyword(s):  
Homogeneous Nucleation ◽  
Nucleation Theory ◽  
Homogeneous Nucleation Theory

Quasi-Homogeneous Nucleation in Microgravity at Low Heat Flux: Experiments and Theory

1997 ◽  
Vol 119 (2) ◽  
pp. 305-312 ◽  
Author(s):  
H. Merte ◽  
H. S. Lee
Keyword(s):  
Heat Flux ◽  
Homogeneous Nucleation ◽  
Constant Pressure ◽  
Heating Surface ◽  
Nucleation Theory ◽  
Bulk Liquid ◽  
Space Experiments ◽  
Low Levels ◽  
Homogeneous Nucleation Theory ◽  
Three Space

Experiments were conducted in the microgravity of space in which a pool of liquid (R-113), initially at a defined pressure and temperature, was subjected to a step imposed heat flux from a semitransparent thin-film heater forming part of one wall of the container such that boiling is initiated and maintained for a defined period of time at a constant pressure level. Measurements of the transient heater surface and fluid temperatures near the surface were made, noting in particular the conditions at the onset of boiling, along with motion photography of the boiling process in two simultaneous views, from beneath the heating surface and from the side. A total of nine tests were conducted at three levels of heat flux and three levels of subcooling. They were repeated under essentially identical circumstances in each of three space experiments. The absence of buoyancy resulted in the onset of boiling at low heat flux levels, with what is defined as quasi-homogeneous nucleation taking place. The influence of these low levels of heat flux and the pressure effect used to produce the bulk liquid subcooling are accounted for by a modification of classical homogeneous nucleation theory.

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