Abstract
In this work, the interaction between electrically charged droplets in microgravity is considered. During the 22 s of microgravity brought by a parabolic flight, water droplets with a radius r ∈ [0.41 − 0.97] mm were released one in front of the other. A high-speed camera allowed studying their interaction in the focal plane. The trajectories of the droplets are well adjusted by a punctual charge model. In some experiments, a physical contact between the charged droplets was observed. These collisions are studied via a phase diagram comparing the droplet Weber number, We, and the collision parameter, χ. By comparing these collisions to experiments involving neutral droplets, we deduce how the collision diagram is affected by electric charges. In particular, we show that the criterion for an impact between two droplets is no more χ < 1.
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Acknowledgments
S. D. acknowledges support as a FNRS Senior Research Associate. M. B. acknowledges support as a FNRS-FRIA Fellow. This work has been financed by the project eDroplets funded by Fonds Spéciaux pour la Recherche (FWB) and by ULG ARC Supercool contract. This research has been also funded by the IAP 7/38 MicroMAST initiated by the Belgian Science Policy Office (BELSPO). The authors would also like to warmly thank B. Darbois-Texier, A. Duchesne, J. Hardouin, Bernard Boigelot, M. Mélard, F. Allegro, and S. Rondia for fruitful discussions and development of the experimental setup. We also want to thanks Novespace for all their help through the development of the experiment and during the study itself.
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Brandenbourger, M., Caps, H., Vitry, Y. et al. Electrically Charged Droplets in Microgravity. Microgravity Sci. Technol. 29, 229–239 (2017). https://doi.org/10.1007/s12217-017-9542-0
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DOI: https://doi.org/10.1007/s12217-017-9542-0