Bretherton Flow in a Finite Cavity
Shadowgraph images are recorded of the formation of bubbles in hydrocarbons in and at cavities in THV, a fluorinated polymer. The cavities are heated with a CW laser, leading to gradients in the surrounding heat distribution. The dynamics depend on the geometry of the cavity, the choice of liquid, a...
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Veröffentlicht in: | Bulletin of the American Physical Society 2004-03, Vol.49 (1) |
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Hauptverfasser: | , , |
Format: | Artikel |
Sprache: | eng |
Online-Zugang: | Volltext |
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Zusammenfassung: | Shadowgraph images are recorded of the formation of bubbles in hydrocarbons in and at cavities in THV, a fluorinated polymer. The cavities are heated with a CW laser, leading to gradients in the surrounding heat distribution. The dynamics depend on the geometry of the cavity, the choice of liquid, and the heating profile. Rather than break off at a location exterior to the cavity, often the cavity fills from the bottom up, with the bubble slowly lifting off. In alkanes the lift rate makes a sharp jump at a critical bubble size. In methanol the fill rate is dramatically higher. As the heating rate is increased inter-cavity bridging occurs. Bridging in long capillaries has been associated with either condensation; here it is induced by bubble growth and is found to be a strong function of the finite length of the cavity. Many liquids give rise to tearing upon wetting the cavities. Flow visualization shows that strong eddy currents can be present around the bubbles |
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ISSN: | 0003-0503 |