Non-conforming finite elements for axisymmetric charged droplet deformation dynamics and Coulomb explosions

Numerical simulation results of the Coulomb explosion pathways of cooled water and heated glycol droplets electrically charged to the critical Rayleigh limit are presented, calculated using an axi-symmetric finite element scheme previously used for the same problem [Radcliffe A. J., Non-conforming finite elements for axisymmetric charged droplet deformation dynamics and Coulomb explosions, Int. J. Num. Meth. Fluids 71:249–268, (2013), doi:10.1002/fld.3667.] which has been adapted to use arbitrary Lagrangian–Eulerian (ALE) methods and a novel tip reconstruction technique in order to greatly improve its accuracy in matching available experimental data.

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Cylindrically and non-cylindrically symmetric expansion dynamics of tin microdroplets after ultrashort laser pulse impact

Applied Physics A ◽

10.1007/s00339-020-04207-9 ◽

2021 ◽

Vol 127 (2) ◽

Author(s):

Tiago de Faria Pinto ◽

Jan Mathijssen ◽

Randy Meijer ◽

Hao Zhang ◽

Alex Bayerle ◽

...

Keyword(s):

Laser Pulse ◽

Laser Pulses ◽

Femtosecond Laser Pulses ◽

Droplet Deformation ◽

Cylindrically Symmetric ◽

Linearly Polarized ◽

Particle Hydrodynamics ◽

Deformation Dynamics ◽

Smoothed Particle ◽

Asymmetric Shock

AbstractIn this work, the expansion dynamics of liquid tin micro-droplets irradiated by femtosecond laser pulses were investigated. The effects of laser pulse duration, energy, and polarization on ablation, cavitation, and spallation dynamics were studied using laser pulse durations ranging from 220 fs to 10 ps, with energies ranging from 1 to 5 mJ, for micro-droplets with an initial radius of 15 and 23 $$\upmu$$ μ m. Using linearly polarized laser pulses, cylindrically asymmetric shock waves were produced, leading to novel non-symmetric target shapes, the asymmetry of which was studied as a function of laser pulse parameters and droplet size. A good qualitative agreement was obtained between smoothed-particle hydrodynamics simulations and high-resolution stroboscopic experimental data of the droplet deformation dynamics.

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The Relation Between Ejection Mechanism and Ion Abundance in the Electric Double Layer of Drops

10.26434/chemrxiv.13788865.v4 ◽

2021 ◽

Author(s):

Victor Kwan ◽

Ryan O'Dwyer ◽

David Laur ◽

Jiahua Tan ◽

Styliani Consta

Keyword(s):

Surface Layer ◽

Chemical Reactivity ◽

Critical Role ◽

Reaction Rates ◽

Mass Spectrometry Data ◽

Charged Droplet ◽

Droplet Deformation ◽

Ion Evaporation ◽

Dynamics Simulations ◽

Evaporation Mechanism

<div> Charged droplets have been associated with distinct chemical reactivity. It is assumed that the composition of the surface layer plays a critical role in enhancing the reaction rates in the droplets relative to their bulk counterparts. We use atomistic modeling to relate the localization of the ions in the surface layer to their ejection propensity. We find that<br>the ion ejection takes place via a two-stage process. Firstly, a conical protrusion emerges as a result of a global droplet deformation that is insensitive to the locations of single ions. The ions are subsequently ejected as they enter the conical regions. The study provides mechanistic insight into the<br> ion-evaporation mechanism, which can be used to revise the commonly used ion-evaporation models. We argue that atomistic molecular dynamics simulations of minute nano-drops, do not sufficiently distinguish the ion-evaporation mechanism from a Rayleigh fission. We explain mass spectrometry data on the charge state of small globular proteins and the existence of super-charged droplet states (above the Rayleigh limit) that have been detected in experiments. <br></div><div><br></div><div><br></div><div><br></div>

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The Relation Between Ejection Mechanism and Ion Abundance in the Electric Double Layer of Drops

10.26434/chemrxiv.13788865 ◽

2021 ◽

Author(s):

Victor Kwan ◽

Ryan O'Dwyer ◽

David Laur ◽

Jiahua Tan ◽

Styliani Consta

Keyword(s):

Surface Layer ◽

Chemical Reactivity ◽

Critical Role ◽

Reaction Rates ◽

Mass Spectrometry Data ◽

Charged Droplet ◽

Droplet Deformation ◽

Ion Evaporation ◽

Dynamics Simulations ◽

Evaporation Mechanism

<div> Charged droplets have been associated with distinct chemical reactivity. It is assumed that the composition of the surface layer plays a critical role in enhancing the reaction rates in the droplets relative to their bulk counterparts. We use atomistic modeling to relate the localization of the ions in the surface layer to their ejection propensity. We find that<br>the ion ejection takes place via a two-stage process. Firstly, a conical protrusion emerges as a result of a global droplet deformation that is insensitive to the locations of single ions. The ions are subsequently ejected as they enter the conical regions. The study provides mechanistic insight into the<br> ion-evaporation mechanism, which can be used to revise the commonly used ion-evaporation models. We argue that atomistic molecular dynamics simulations of minute nano-drops, do not sufficiently distinguish the ion-evaporation mechanism from a Rayleigh fission. We explain mass spectrometry data on the charge state of small globular proteins and the existence of super-charged droplet states (above the Rayleigh limit) that have been detected in experiments. <br></div><div><br></div><div><br></div><div><br></div>

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