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ISSN Online: 2377-424X

ISBN Print: 978-1-56700-474-8

ISBN Online: 978-1-56700-473-1

International Heat Transfer Conference 16
August, 10-15, 2018, Beijing, China

SPREADING AND SPLASHING OF A DROPLET TRAIN IMPINGING ONTO A HEATED NANOTUBE SURFACE

Get access (open in a dialog) DOI: 10.1615/IHTC16.bae.023426
pages 951-956

Résumé

The dynamic impingements of an ethanol droplet train onto a superheated solid surface are visualized with a high-speed camera, and then analyzed. The droplet train has a velocity of 19.4 m/s and a frequency of 40.99 kHz. Distinct hydrodynamic patterns are revealed by varying the surface temperatures (ranging from 120 °C to 450 °C). Three regimes are identified based on the patterns, namely, boiling zone, transition zone and film boiling zone. The wetting area highly depends on the surface temperature. It becomes a constant when the balance between the ethanol consumption and the supply is achieved. The time-independent wetting diameter decreases with an increase in the surface temperature in the boiling zone and keeps as a constant in the transition zone. Whereas, the wetting diameter has a mild increase in the post-transition zone since the spreading is enhanced by the generated thin vapor layer when the surface temperature is higher than the Leidenfrost point. Besides, the formation of crown sheet is observed in the boiling zone. The steady splashing angle is seen in the transition and post-transition zone.