Splashing of high speed droplet train impinging on a hot surface
Choo, Fook Hoong
Date of Issue2015
School of Mechanical and Aerospace Engineering
Energy Research Institute
Transition phenomena are observed when a water droplet train (with up to 18.9 m/s in velocity and 39.20 kHz in frequency) impinges onto a heated copper surface (up to 250 °C). The hydrodynamic flow pattern strongly depends on the wall temperature. The surface temperature does not apparently influence the spreading speed when the wall temperature is less than the boiling temperature, but it enhances the spreading rate significantly at higher surface temperatures. A “steady-state” wetting surface area can be reached when the water supply rate equals the water consumption rate. The time-independent spreading diameter decreases with an increase in the wall temperature until an ultimate diameter of the “steady-state” wetting area is observed at around 0.4 mm, 3.4 times the droplet diameter, when the surface temperature is higher than 190 °C. Moreover, unlike the random direction splashing when wall temperature is less than 180 °C, a stable splashing angle is established at higher wall temperatures. However, the angle reduces apparently with the increase in the wall temperature.
Applied Physics Letters
© 2015 AIP Publishing LLC. This paper was published in Applied Physics Letters and is made available as an electronic reprint (preprint) with permission of AIP Publishing LLC. The published version is available at: [http://dx.doi.org/10.1063/1.4934531]. One print or electronic copy may be made for personal use only. Systematic or multiple reproduction, distribution to multiple locations via electronic or other means, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper is prohibited and is subject to penalties under law.