Scattering properties and scattering kernel based on the molecular dynamics analysis of gas-wall interaction

Yamamoto, Kazuomi; Takeuchi, Hideki; Hyakutake, Toru

doi:10.1063/1.2770513

Cited by 46 publications

(28 citation statements)

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“…Interaction of gas molecules with channel surface is described in terms of scattering kernel. For specific combination of gas and membrane material, the parameters of the kernel (and the scattering model itself) can be obtained from molecular dynamics trajectories computations [9,10,11]. The choice of the theoretical model to describe scattering in a number of problem appears to be fundamental.…”

Section: Problem Statementmentioning

confidence: 99%

Free-molecular gas flow through the high-frequency oscillating membrane

Kovalev

Yakunchikov

Kosiantchouk

2016

J. Phys.: Conf. Ser.

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Free-molecular gas flow through the highfrequency oscillating membrane Abstract. The possibility of using a high frequency oscillating track membranes as diffusion membranes for gas separation was studied. High frequency forced oscillation of the membrane was considered because of assumption that the membrane conductivity for a given gas can be controlled by varying the frequency and amplitude of oscillation. The problem about freemolecular gas flow through a oscillating in its plane membrane was stated and the possibility of separation of gases using such a device was investigated. Also, optimal values of membrane oscillation parameters for most efficient gas separation have been found.

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Section: Problem Statementmentioning

confidence: 99%

Free-molecular gas flow through the high-frequency oscillating membrane

Kovalev

Yakunchikov

Kosiantchouk

2016

J. Phys.: Conf. Ser.

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“…[13], the Maxwell model, denoted as the extended Maxwell model throughout the paper, is able to produce the accurate reflected velocity distribution if the system is slightly nonequilibrium. When the incident gas molecules are in a highly nonequilibrium state, such as that in molecular beam experiments, none of the existing gas-wall interaction models performs well [14,16]. The majority of previous studies focused on the reflected molecular velocity distribution or the correlation between the incident and reflected molecular velocities.…”

Section: Introductionmentioning

confidence: 99%

“…For applications in high-speed rarefied gas, significant work has been conducted on model validation [15]. For micro-and nanoscale gas flows, considerate efforts have recently been put forth to evaluate the empirical models by comparing the predicted molecular velocity distribution functions with those obtained from molecular dynamics (MD) simulations in simple problems such as Couette shear flow and the Fourier thermal problem [13,14,16,17]. These studies have shown that when the incident gas molecules are not in an equilibrium state, the reflected velocity distribution predicted by Maxwell model cannot match well with MD results.…”

Section: Introductionmentioning

confidence: 99%

“…To devise a rigorous and accurate gas-wall interaction model in a general setting is extremely challenging due to the complex molecular scattering process. Hence, various empirical gas-wall interaction models [7][8][9][10][11][12][13][14], developed initially for the modeling of high-speed rarefied gas, have been constructed to formulate the phenomenological relation between the molecular velocity distribution functions of the incident and the reflected gas molecules and have achieved certain success in numerous applications related to high-speed rarefied gas. Typically, one or several parameters, called the accommodation coefficients (ACs), are required in these models.…”

Section: Introductionmentioning

confidence: 99%

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Performance evaluation of Maxwell and Cercignani-Lampis gas-wall interaction models in the modeling of thermally driven rarefied gas transport

Liang

2013

Phys. Rev. E

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CitationPerformance evaluation of Maxwell and CercignaniLampis gas-wall interaction models in the modeling of thermally driven rarefied gas transport 2013, 88 (1) Physical Review E A systematic study on the performance of two empirical gas-wall interaction models, the Maxwell model and the Cercignani-Lampis (CL) model, in the entire Knudsen range is conducted. The models are evaluated by examining the accuracy of key macroscopic quantities such as temperature, density, and pressure, in three benchmark thermal problems, namely the Fourier thermal problem, the Knudsen force problem, and the thermal transpiration problem. The reference solutions are obtained from a validated hybrid DSMC-MD algorithm developed in-house. It has been found that while both models predict temperature and density reasonably well in the Fourier thermal problem, the pressure profile obtained from Maxwell model exhibits a trend that opposes that from the reference solution. As a consequence, the Maxwell model is unable to predict the orientation change of the Knudsen force acting on a cold cylinder embedded in a hot cylindrical enclosure at a certain Knudsen number. In the simulation of the thermal transpiration coefficient, although all three models overestimate the coefficient, the coefficient obtained from CL model is the closest to the reference solution. The Maxwell model performs the worst. The cause of the overestimated coefficient is investigated and its link to the overly constrained correlation between the tangential momentum accommodation coefficient and the tangential energy accommodation coefficient inherent in the models is pointed out. Directions for further improvement of models are suggested.

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“…The accommodation coefficients can also be found by comparison with Monte Carlo [122,118] or Molecular Dynamics [123,124] calculations. The surface data may be imported via atomic force microscopy on a real surface [125] or may be generated according to the wall characteristics [124,123].…”

Section: Boundary Conditionsmentioning

confidence: 99%

Simulation of transport phenomena in conditions far from thermodynamic equilibrium via kinetic theory with applications in vacuum technology and MEMS

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The approval of the current dissertation by the Department of Mechanical Engineering of the University of Thessaly does not imply acceptance of the author's opinions (Law 5343/32 number 202 paragraph 2). Also, the views and opinions expressed herein do not necessarily reflect those of the European Commission. There are several other people who I feel that have contributed in the writing of this dissertation.The most important contributions, along with several helpful conversations, were made by Prof. F.Sharipov, who provided the basic concept of the channel end effect study, and Dr. Chr. Day along with the KIT personnel, who briefly introduced me in the world of experimental rarefied gas dynamics. It was also a priviledge to discuss and work for a brief period of time with Prof. A. Grecos, who tirelessly discussed with me on various subjects of statistical mechanics. Financial support for this Ph.D. has been provided by the Euratom Association -Hellenic Republic, to which I am deeply indepted. Also, partial support for conference mobility expenses has been received from the GASMEMS Marie Curie programme. In this work, non-equilibrium transport phenomena have been examined via the kinetic theory of gases. The behaviour of the gas in low pressure conditions or in low-dimensionality systems can not be captured by the usual Navier-Stokes formulation, in conjunction with the constitutive laws of Newton-Fourier-Fick. The limited number of intermolecular collisions results in departure from equilibrium and the particulate nature of the gas must be taken into account, greatly increasing the computational effort.The problem is described by the integro-differential Boltzmann equation, which is used to determine the distribution of particles in physical and molecular velocity space, as well as in time.There are difficulties associated with the seven-dimensional nature of the distribution function, as well as with the complexity of the collision term, which is usually substituted by an appropriate model.The most widely used and successful numerical methodologies, the Discrete Velocity Method (DVM) and the Direct Simulation Monte Carlo (DSMC), are applied here in the whole range of the Knudsen number. It is important to employ approaches based on kinetic theory, since these are the only ones which are valid for any rarefaction level.In this work, several problems including non-equilibrium phenomena are considered. The interaction of gases with solid surfaces is considered for several problems according to the CercignaniLampis boundary conditions. The non-linear form of this scattering kernel, which had not been pre- viously used in the literature, is applied on the problem of heat transfer between parallel plates and coaxial cylinders. Its linearized form has also been employed for both flow and heat transfer problems and a comparison with relevant experiments has lead to surface characterization with respect to argon and helium flows.Non-linear heat conduction phenomena are also studied for the parallel plates and coaxial c...

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Scattering properties and scattering kernel based on the molecular dynamics analysis of gas-wall interaction

Cited by 46 publications

References 7 publications

Free-molecular gas flow through the high-frequency oscillating membrane

Free-molecular gas flow through the high-frequency oscillating membrane

Performance evaluation of Maxwell and Cercignani-Lampis gas-wall interaction models in the modeling of thermally driven rarefied gas transport

Simulation of transport phenomena in conditions far from thermodynamic equilibrium via kinetic theory with applications in vacuum technology and MEMS

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