Kinetic boundary conditions for vapor–gas binary mixture

Kobayashi, Kazumichi; Sasaki, Kiyofumi; Kon, Masafumi; Fujii, Hiroyuki; Watanabe, Masao

doi:10.1007/s10404-017-1887-6

Cited by 43 publications

(39 citation statements)

References 28 publications

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“…Among them, the assessment of the boundary conditions commonly adopted at the liquid-vapor interface has certainly the prominent role [18]. The need for a deeper understanding of the complexities of interfacial phenomena has triggered a number of studies based on molecular dynamics (MD) simulations of Lennard-Jones single-component [19][20][21][22] and, more recently, multicomponent fluids [23,24]. In contrast to studies based on the Boltzmann equation, MD simulations are able to model both the liquid and vapor phases within the same framework, although the high computational cost hinders their extensive use in systematic investigations.…”

Section: Introductionmentioning

confidence: 99%

Mean-field kinetic theory approach to evaporation of a binary liquid into vacuum

et al. 2018

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Evaporation of a binary liquid into near-vacuum conditions has been studied using numerical solutions of a system of two coupled Enskog-Vlasov equations. Liquid-vapor coexistence curves have been mapped out for different liquid compositions. The evaporation process has been investigated at a range of liquid temperatures sufficiently lower than the critical one for the vapor not to significantly deviate from the ideal behavior. It is found that the shape of the distribution functions of evaporating atoms is well approximated by an anisotropic Maxwellian distribution with different characteristic temperatures for velocity components normal and parallel to the liquid-vapor interface. The anisotropy reduces as the evaporation temperature decreases. Evaporation coefficients are computed based on the separation temperature and the maximum concentration of the less volatile component close to the liquid-vapor interface. This choice leads to values which are almost constant in the simulation conditions.

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Section: Introductionmentioning

confidence: 99%

Mean-field kinetic theory approach to evaporation of a binary liquid into vacuum

et al. 2018

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“…The current MCE plates enable the generation of monodispersed droplets of 1 to 500 μm [8,9]. The smallest sizes are only possible with grooved-type MCEs with limited droplet productivity.…”

Section: Introductionmentioning

confidence: 99%

“…Previous MCE plates, which have the capacity of generating small-sized droplets, had a very low droplet productivity since these plates operate at a low dispersed-phase flow rate (Q d ) and with a relatively small number of MCs. The straight-through MCE plates are capable to operate at high Q d of > 10 mL h -1 but can only produce droplets of > 25 to 32 μm and are highly depending on the viscosity of the dispersed phase [9,13]. Vladisavljevic, Kobayashi, and Nakajima [13] stated increased droplet generation from MCs with decreasing dispersed-phase viscosity.…”

Section: Introductionmentioning

confidence: 99%

Asymmetrical Microchannel Emulsification Plates for Production of Small‐Sized Monodispersed Emulsion Droplets

et al. 2017

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Monodispersed emulsion droplets have promising advantages in food, pharmaceutical, and chemical industries. Previous microchannel emulsification (MCE) plates having the capacity of generating small‐sized droplets exhibited very low droplet productivity since these plates operate at a low dispersed‐phase flow rate and with a relatively small number of microchannels. An innovative MCE plate with 176 176 circular asymmetric through‐holes was manufactured, which is comprised of a series of discrete outlets on each microchannel line with an effective cross‐sectional area of 1 cm2. The newly fabricated MCE plate is capable to produce monodispersed emulsion droplets with small Sauter mean diameters.

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“…The authors of ref. 34 noted that there is a deviation from the Maxwellian VDF for particles flying in the direction normal to the interfacial surface: "However, the detailed mechanism of the deviation has not been clarified yet. "…”

mentioning

confidence: 99%

“…Numerous papers using the MD method indicate that an important question in determining the KBC is at which position of the boundary between the liquid and gas phases those KBC should be determined (27,32,34,35). The authors of ref.…”

mentioning

confidence: 99%

Mass and heat transfer between evaporation and condensation surfaces: Atomistic simulation and solution of Boltzmann kinetic equation

Zhakhovsky

Kryukov

Levashov

et al. 2018

Proc. Natl. Acad. Sci. U.S.A.

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Boundary conditions required for numerical solution of the Boltzmann kinetic equation (BKE) for mass/heat transfer between evaporation and condensation surfaces are analyzed by comparison of BKE results with molecular dynamics (MD) simulations. Lennard-Jones potential with parameters corresponding to solid argon is used to simulate evaporation from the hot side, nonequilibrium vapor flow with a Knudsen number of about 0.02, and condensation on the cold side of the condensed phase. The equilibrium density of vapor obtained in MD simulation of phase coexistence is used in BKE calculations for consistency of BKE results with MD data. The collision cross-section is also adjusted to provide a thermal flux in vapor identical to that in MD. Our MD simulations of evaporation toward a nonreflective absorbing boundary show that the velocity distribution function (VDF) of evaporated atoms has the nearly semi-Maxwellian shape because the binding energy of atoms evaporated from the interphase layer between bulk phase and vapor is much smaller than the cohesive energy in the condensed phase. Indeed, the calculated temperature and density profiles within the interphase layer indicate that the averaged kinetic energy of atoms remains near-constant with decreasing density almost until the interphase edge. Using consistent BKE and MD methods, the profiles of gas density, mass velocity, and temperatures together with VDFs in a gap of many mean free paths between the evaporation and condensation surfaces are obtained and compared. We demonstrate that the best fit of BKE results with MD simulations can be achieved with the evaporation and condensation coefficients both close to unity.

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Kinetic boundary conditions for vapor–gas binary mixture

Cited by 43 publications

References 28 publications

Mean-field kinetic theory approach to evaporation of a binary liquid into vacuum

Mean-field kinetic theory approach to evaporation of a binary liquid into vacuum

Asymmetrical Microchannel Emulsification Plates for Production of Small‐Sized Monodispersed Emulsion Droplets

Mass and heat transfer between evaporation and condensation surfaces: Atomistic simulation and solution of Boltzmann kinetic equation

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