A vapor bubble developing at a nucleation site on a superheated wall is modeled as a spherical segment whose base is separated from the wall by a thin liquid microlayer. Two dynamic equations are derived from a variational equation of conservation of the mechanical energy for the system composed of the bubble and the surrounding liquid. These equations serve to find the bubble radius and the height of its center above the wall. They are completely free from arbitrary assumptions made by authors of previous models. When being attached to the wall, the bubble evolves under action of buoyancy and of an effective surface tension force, and ultimately detaches due to the same forces. The moment of detachment comes as the height of the bubble center draws equal to its radius. Our model is applied to nearly spherical bubbles of thermally-controlled growth with allowance made for evaporation from the microlayer as well as from the bulk of ambient liquid. Gravitational effects on the duration of bubble evolution, bubble growth rate, and the bubble departure size are treated. The conclusions inferred by the model are in satisfactory agreement with experimental results.
Modeling of vapor bubble growth under nucleate boiling conditions in reduced gravity
Modellierung des Dampfblasenwachstums unter Bedingungen des Blasensiedens in verminderter Schwerkraft
1995
8 Seiten, 6 Bilder, 21 Quellen
Aufsatz (Konferenz)
Englisch
Nucleate Pool Boiling of Water in Normal and Reduced Gravity Environments
SAE Technical Papers | 1994
|British Library Conference Proceedings | 2001
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