Binary collisions of equal-sized water nanodroplets: Molecular dynamics simulations

Yin, Zongjun; Su, Rong; Zhang, Wenfeng; Zhang, Chunying; Xu, Hui; Hu, Hanchun; Zhang, Zhendong; Huang, Bensheng; Liu, Fengguang

doi:10.1016/j.commatsci.2021.110774

Cited by 4 publications

(3 citation statements)

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“…Using α obtained by the model of β max in the cross-over regime, the prefactor, C ∼ (1 − α) −1 , of (3.1) is also determined, which shows good agreement with the data in the cross-over regime, as shown in figure 6(e). It should be emphasised that the value of C regressed from the phase diagram of Yin et al (2021), who simulated the collisions by two TIP4P water nanodroplets, is also satisfactorily predicted by C ∼ (1 − α) −1 , indicating that the collision dynamics obtained by different potential models of liquids is the same when the value of the dimensionless number group remains constant. This further proves that it is safe to investigate binary nanodroplet collisions by such a coarse-grained mW water model.…”

Section: Modelling β Max In a Vacuummentioning

confidence: 82%

“…To validate whether this scaling law covers the stretching separation boundary in both the inertial and cross-over regimes, another two phase diagrams for mW nanodroplets with Oh = 0.39 ( D 0 = 8 nm) and 0.45 ( D 0 = 6 nm) from this work are shown in figure 6( a , b ), and an additional phase diagram for TIP4P nanodroplets with Oh = 0.58 from Yin et al . (2021) is shown in figure S8. Moreover, the experimental data on the stretching separation boundaries from the previous studies (Sommerfeld & Kuschel 2016; Sommerfeld & Pasternak 2019; Al-Dirawi et al .…”

Section: Resultsmentioning

confidence: 99%

“…Recently, there have been studies on the binary nanodroplet collision, including outcome regimes and modelling β max . Yin et al (2021) investigated collisions of nanodroplets in a vacuum and found that Regimes BO, RES and ROS do not take place at the nanoscale in the tested We range from 0 to 300; as a result, Regimes CO, SS and SH occupy most regions of the phase diagram at the nanoscale. The strongly suppressed Regimes RES and ROS at the nanoscale accord with the macroscale feature in the cross-over regime and hence confirm the speculation that the binary nanodroplet collision falls into the cross-over regime.…”

Section: Introductionmentioning

confidence: 99%

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Binary collision dynamics of equal-sized nanodroplets

Wang,

Cai

et al. 2024

J. Fluid Mech.

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Binary nanodroplet collisions have received increasing attention, whilst the identification of collision outcomes and the viscous dissipation mechanism have remained poorly understood. Using molecular dynamics simulations, this study investigates binary nanodroplet collisions over wide ranges of Weber number (We), Ohnesorge number (Oh) and off-centre distances. Coalescence, stretching separation and shattering are identified; however, bouncing, reflexive separation and rotational separation reported for millimetre-sized collisions are not observed, which is attributed to the enhanced viscous effect caused by the ‘natural’ high-viscosity characteristics of nanodroplets. Intriguingly, as an intermediate outcome, holes form in retracting films at relatively high We, arising from the vibration and thermal fluctuation of the films. Due to the combined effects of inertial, capillary and viscous forces, binary nanodroplet collisions fall into the cross-over regime, so estimating viscous dissipation becomes extremely important for distinguishing outcome boundaries. Based on the criterion that stretching separation is triggered only when the residual off-centre kinetic energy exceeds the surface energy required for separation, the boundary equation between coalescence and stretching separation is established. Here, viscous dissipation is calculated by the extracted flow feature from simulations, showing that the ratio of viscous dissipation to the initial kinetic energy depends only on Oh, not on We. Because of complex viscous dissipation mechanisms, the same boundary equation in the cross-over regime has also not been satisfactorily revealed for macroscale collisions. Therefore, the proposed equation is tested for wide data sources from both macroscale and nanoscale collisions, and satisfying agreement is achieved, demonstrating the universality of the equation.

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Section: Modelling β Max In a Vacuummentioning

confidence: 82%