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Main Authors: Prasanna, Anunay, Biasiori-Poulanges, Luc, Yu, Ya-Chi, El-Rabii, Hazem, Lukić, Bratislav, Supponen, Outi
Format: Preprint
Published: 2023
Subjects:
Online Access:https://arxiv.org/abs/2309.15012
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author Prasanna, Anunay
Biasiori-Poulanges, Luc
Yu, Ya-Chi
El-Rabii, Hazem
Lukić, Bratislav
Supponen, Outi
author_facet Prasanna, Anunay
Biasiori-Poulanges, Luc
Yu, Ya-Chi
El-Rabii, Hazem
Lukić, Bratislav
Supponen, Outi
contents Ultrasonic atomization is employed to generate size-controllable droplets for a variety of applications. Here, we minimize the number of parameters dictating the process by studying the atomization of a single drop pending from an ultrasonic horn. Spatiotemporally resolved X-ray phase-contrast imaging measurements show that the number-median sizes of the ejected droplets can be predicted by the linear Navier-Stokes equations, signifying that the size distribution is controlled by the fluid properties and the driving frequency. Experiments with larger pendant water drops indicate that the fluid-structure interaction plays a pivotal role in determining the ejection onset of the pendant drop. The atomization of viscoelastic drops is dictated by extended ligament formation, entrainment of air, and ejection of drop-encapsulated bubbles. Existing scaling laws are used to explain the required higher input amplitudes for the complete atomization of viscoelastic drops as compared to inviscid drops. Finally, we elucidate the differences between capillary wave-based and cavitation-based atomization and show that inducing cavitation and strong bubble oscillations quickens the onset of daughter drop ejection but impedes their size control.
format Preprint
id arxiv_https___arxiv_org_abs_2309_15012
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Synchrotron X-ray phase-contrast imaging of ultrasonic drop atomization
Prasanna, Anunay
Biasiori-Poulanges, Luc
Yu, Ya-Chi
El-Rabii, Hazem
Lukić, Bratislav
Supponen, Outi
Fluid Dynamics
Ultrasonic atomization is employed to generate size-controllable droplets for a variety of applications. Here, we minimize the number of parameters dictating the process by studying the atomization of a single drop pending from an ultrasonic horn. Spatiotemporally resolved X-ray phase-contrast imaging measurements show that the number-median sizes of the ejected droplets can be predicted by the linear Navier-Stokes equations, signifying that the size distribution is controlled by the fluid properties and the driving frequency. Experiments with larger pendant water drops indicate that the fluid-structure interaction plays a pivotal role in determining the ejection onset of the pendant drop. The atomization of viscoelastic drops is dictated by extended ligament formation, entrainment of air, and ejection of drop-encapsulated bubbles. Existing scaling laws are used to explain the required higher input amplitudes for the complete atomization of viscoelastic drops as compared to inviscid drops. Finally, we elucidate the differences between capillary wave-based and cavitation-based atomization and show that inducing cavitation and strong bubble oscillations quickens the onset of daughter drop ejection but impedes their size control.
title Synchrotron X-ray phase-contrast imaging of ultrasonic drop atomization
topic Fluid Dynamics
url https://arxiv.org/abs/2309.15012