Heat and mass transfer at condensate–vapor interfaces

Kryukov, A. P.; Levashov, Vladimir Yur’evich; Жаховский, В. В.; Anisimov, S. I.

doi:10.3367/ufne.2020.04.038749

Cited by 10 publications

(7 citation statements)

References 79 publications

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“…The left boundary condition at x = 0 must determine a velocity distribution function f 1 for atoms moving from the condensation surface after evaporation or reflection, while f 2 for incoming atoms should be obtained via solution of the moment equations (4). Assuming the diffuse nature of reflection and evaporation processes it can be written as follows…”

Section: B Bke and Moment Methods For Steady Condensationmentioning

confidence: 99%

“…Application of the Boltzmann kinetic equation (BKE) and its simplified models in such conditions gave new insight into the processes associated with evaporation and condensation. As a result, the quantitative descriptions of many experiments were obtained, and the ranges of various regimes of evaporation/condensation processes were determined 4 .…”

Section: Introductionmentioning

confidence: 99%

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Subsonic and supersonic gas flows to condensation surface

Kryukov,

Zhakhovsky,

Levashov

2022

Preprint

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Intense heat-mass transfer in a gas flow to a condensation surface is studied with the consistent atomistic and kinetic theory methods. The simple moment method is utilized for solving the Boltzmann kinetic equation (BKE) for the nonequilibrium gas flow and its condensation, while molecular dynamics (MD) simulation of a similar flow is used for verification of BKE results. We demonstrate that BKE can provide the steady flow profiles close to those obtained from MD simulations in both subsonic and supersonic regimes of steady gas flows. Surprisingly, the elementary theory of condensation is shown with BKE results to have a good accuracy in a wide range of gas flow parameters.MD confirms that a steady supersonic gas flow condensates on a surface at the distinctive temperature after formation of a standing shock front in reference to this surface, which can be interpreted as a permeable condensating piston. The last produces the shock compression but completely absorbs incoming gas flow in contrast to a common impermeable piston. The shock front divides the vapor flow on the supersonic and subsonic zones, and condensation of compressed gas happens in the subsonic regime. The complete and partial condensation regimes are discussed. It is shown that above the certain surface temperatures determined by the shock Hugoniot the runaway shock front stops an inflow gas and condensation is ceased.

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Section: B Bke and Moment Methods For Steady Condensationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Subsonic and supersonic gas flows to condensation surface

Kryukov,

Zhakhovsky,

Levashov

2022

Preprint

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“…In our case, these are states with densities from the critical to solid-state value and with temperatures one or two orders of magnitude higher than the critical temperature T cr , i.e., states far above the binodal on the (ρ, T) plane; the binodal is the line of equilibrium coexistence of the gas and condensed phases. At the same time, dense media (crystals, liquids) and gases are described by the potential well up to the temperature T cr [23][24][25].…”

Section: Numerical Simulationmentioning

confidence: 99%

Melting of Titanium by a Shock Wave Generated by an Intense Femtosecond Laser Pulse

et al. 2022

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Laser shock peening with ultrashort laser pulses has been studied by hydrodynamic and atomistic simulations, as well as experimentally. It has been shown that, in contrast to traditional nanosecond pulses, ultrashort laser pulses allow one to increase the produced pressures by two or three orders of magnitude from 1–10 GPa to 1000 GPa (1 TPa). The physics of phenomena changes fundamentally because shock waves generating pressures exceeding the bulk modulus of a metal melt it. It has been shown for the first time that the shock melting depth at pressures about 1 TPa is an order of magnitude larger than the thickness of the melt layer caused by heat conduction. The appearance, propagation, and damping of a melting shock wave in titanium have been studied. The damping of the shock wave makes it possible to modify the surface layer, where the melting regime changes from a fast one in the shock jump to a slow propagation of the melting front in the unloading tail behind the shock wave. It has been shown experimentally that the ultrafast crystallization of the melt forms a solid layer with a structure strongly different from that before the action. The measured depth of this layer is in good agreement with the calculation.

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“…Here v n and v s are the mesoscopic velocities of the normal and superfluid components (averaged over a small volume Λ), p n and p s is the effective pressures acting on the normal and superfluid component, respectively, (∇p n = ∇p + (ρ s /2)∇w 2 and ∇p s = ∇p − (ρ n /2)∇w 2 ), p is the total pressure, S is the entropy, T is the absolute temperature, η is the dynamic viscosity of the normal component, and…”

Section: Treatment Of Normal Velocity V Nmentioning

confidence: 99%

“…This theme has been widely discussed recently [1]. Knowledge of patterns of formation and development of vapor films on the surface of heaters is important for solving the corresponding problems [2][3][4][5]. Another series of examples are problems associated with the evolution of bubbles created by electrons [6][7][8].…”

Section: Introductionmentioning

confidence: 99%

Rayleigh Problem in Superfluid Helium

Nemirovskii

2021

J. Engin. Thermophys.

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On the basis of the two-fluid hydrodynamics, an analogue of the well-known Rayleigh equation was obtained for the dynamics of a spherical cavity in superfluid helium. With the aim of choosing a correct set of variables, a thorough analysis of the momentum flux tensor and energy flux has been carried out. The mass flux density or the mass average velocity, associated with it, and the velocity of the normal component, were chosen as independent variables. Due to the nonlinear character of the momentum flux tensor, several additional terms appeared in the equation for the evolution of the interface in comparison with the classical Rayleigh equation. These additional terms led to fundamental difference in the dynamics of vapor film in comparison with a classical fluid. For instance, one of the new terms led to an interesting effect of anomalous suppression or, depending on the configuration, anomalous enhancement of oscillations of the interface, observed in many works. Besides the additional anomalous decay or anomalous enhancement, there is also additional pressure, associated with the relative velocity in superfluid helium. The result obtained indicates the need to revise some results on the dynamics of a cavity in superfluid helium.

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Heat and mass transfer at condensate–vapor interfaces

Cited by 10 publications

References 79 publications

Subsonic and supersonic gas flows to condensation surface

Subsonic and supersonic gas flows to condensation surface

Melting of Titanium by a Shock Wave Generated by an Intense Femtosecond Laser Pulse

Rayleigh Problem in Superfluid Helium

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