TY - JOUR
T1 - Secondary atomization of water-in-oil emulsion drops impinging on a heated surface in the film boiling regime
AU - Piskunov, Maxim
AU - Breitenbach, Jan
AU - Schmidt, J. Benedikt
AU - Strizhak, Pavel
AU - Tropea, Cameron
AU - Roisman, Ilia V.
N1 - Funding Information:
The reported study was funded by RFBR, project number 20-31-70021. This research was also supported by the the German Scientific Foundation (Deutsche Forschungsgemeinschaft) in the framework of the SFB-TRR 75 Collaborative Research Center, subproject C4. The authors gratefully thank Johannes Kissing for providing his particle tracking algorithm.
Publisher Copyright:
© 2020 Elsevier Ltd
Copyright:
Copyright 2020 Elsevier B.V., All rights reserved.
PY - 2021/2
Y1 - 2021/2
N2 - The present study experimentally examines the secondary atomization arising from the impingement of a water-in-oil emulsion drop onto a hot sapphire glass surface. The main aim of this study is to characterize secondary droplets emerged from the rim and lamella disruption. Drop impacts of n-dodecane and emulsions with a water volume content of 1.98%, 4.95%, 9.90% and 19.80% have been observed using a high-speed video system. The impact velocity and the target initial temperature have been varied. It is shown that the maximum spreading diameter of the impinging drop, the typical dimensionless diameter of the secondary drops, as well as the number of secondary drops correlate well with the Weber number for a pure liquid. Corresponding scaling relations Dmax∼D0We1/2, D32∼D0We−1/2 and N∼We3/2 in the limit We≫1 are derived by considering the dynamics of spreading and breakup. The size of the secondary drops is reduced significantly for high emulsion concentrations. This effect is explained by the stabilizing role of the water drops in the emulsion, whose surface tension is much higher than the surface tension of the bulk liquid.
AB - The present study experimentally examines the secondary atomization arising from the impingement of a water-in-oil emulsion drop onto a hot sapphire glass surface. The main aim of this study is to characterize secondary droplets emerged from the rim and lamella disruption. Drop impacts of n-dodecane and emulsions with a water volume content of 1.98%, 4.95%, 9.90% and 19.80% have been observed using a high-speed video system. The impact velocity and the target initial temperature have been varied. It is shown that the maximum spreading diameter of the impinging drop, the typical dimensionless diameter of the secondary drops, as well as the number of secondary drops correlate well with the Weber number for a pure liquid. Corresponding scaling relations Dmax∼D0We1/2, D32∼D0We−1/2 and N∼We3/2 in the limit We≫1 are derived by considering the dynamics of spreading and breakup. The size of the secondary drops is reduced significantly for high emulsion concentrations. This effect is explained by the stabilizing role of the water drops in the emulsion, whose surface tension is much higher than the surface tension of the bulk liquid.
KW - Drop impact
KW - Emulsion
KW - Film boiling
KW - Long-wave Marangoni instability
KW - Rayleigh-Taylor instability
KW - Secondary atomization
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U2 - 10.1016/j.ijheatmasstransfer.2020.120672
DO - 10.1016/j.ijheatmasstransfer.2020.120672
M3 - Article
AN - SCOPUS:85096852011
VL - 165
JO - International Journal of Heat and Mass Transfer
JF - International Journal of Heat and Mass Transfer
SN - 0017-9310
M1 - 120672
ER -