Using a static contact angle as a main experimental parameter, photographic study was carried out to investigate the dynamics of vapor bubbles during subcooled pool boiling on a vertical heated surface. Test fluid was distilled water and the experiments were performed under the atmospheric pressure; liquid subcooling was set to around 5 K. To enable clear observation of bubble behavior with a high speed camera, the experiments were conducted in an isolated bubble regime near the onset of nucleate boiling. Distinctly different bubble behaviors were observed on hydrophobic and hydrophilic surfaces: the bubbles were adhered to the surface for a long period of time when the contact angle was large while lifted off the surface within a short period of time after the nucleation when the contact angle was small. Since buoyancy does not remove the bubble from a vertical surface, mechanisms of lift-off were investigated. It was shown that the change in bubble shape induced by the surface tension force, unsteady growth force and local liquid flow induced by heterogeneous condensation around the bubble are considered to promote the bubble lift-off and the surface tension force acting on the three-phase common line prevents the lift-off. Dependences of bubble size and time at lift-off and the condensation rate on the surface wettability were also investigated.
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17th International Conference on Nuclear Engineering
July 12–16, 2009
Brussels, Belgium
Conference Sponsors:
- Nuclear Engineering Division
ISBN:
978-0-7918-4353-6
PROCEEDINGS PAPER
Photographic Study on Bubble Motion in Subcooled Pool Boiling Available to Purchase
Tomio Okawa,
Tomio Okawa
Osaka University, Suita, Osaka, Japan
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Takahiro Harada,
Takahiro Harada
Osaka University, Suita, Osaka, Japan
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Yuta Koutsusa
Yuta Koutsusa
Osaka University, Suita, Osaka, Japan
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Tomio Okawa
Osaka University, Suita, Osaka, Japan
Takahiro Harada
Osaka University, Suita, Osaka, Japan
Yuta Koutsusa
Osaka University, Suita, Osaka, Japan
Paper No:
ICONE17-75387, pp. 367-374; 8 pages
Published Online:
February 25, 2010
Citation
Okawa, T, Harada, T, & Koutsusa, Y. "Photographic Study on Bubble Motion in Subcooled Pool Boiling." Proceedings of the 17th International Conference on Nuclear Engineering. Volume 3: Thermal Hydraulics; Current Advanced Reactors: Plant Design, Construction, Workforce and Public Acceptance. Brussels, Belgium. July 12–16, 2009. pp. 367-374. ASME. https://doi.org/10.1115/ICONE17-75387
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