Numerical simulation of rarefied gas flow through a thin orifice

Sharipov, Felix

doi:10.1017/s0022112004000710

Cited by 104 publications

(60 citation statements)

References 36 publications

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“…3 and 4, is contributed to the size of the downstream computational domain which is not adequately large. Increasing further the size of the downstream container will eliminate this behavior but it will greatly increase the computational e¨ort, while as shown in [12], it is expected to have a negligible e¨ect on the overall quantities of practical interest of the present work.…”

Section: Resultsmentioning

confidence: 94%

Parametric study on propulsion performance of microtubes

Tantos

Valougeorgis

2017

Progress in Flight Physics

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The pressure-driven rare¦ed gas §ow of polyatomic gases through short tubes in a wide range of the Knudsen number is numerically investigated. The downstream over the upstream pressure ratio is taken very close to zero. Such §ows are characterized by low Reynolds numbers and high viscous losses and, therefore, short circular microtubes may be used instead of typical micronozzles. The main computed quantities include the §ow rate, the discharge coe©cient, the thrust, and the impulse factor which are provided in terms of the gas rarefaction and the tube dimensionless length. Based on the above, a parametric study on the propulsion characteristics of microtubes is provided. Furthermore, a comparison between corresponding polyatomic and monoatomic results is performed and the e¨ect of the internal degrees of freedom on the results is investigated.

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Section: Resultsmentioning

confidence: 94%

Parametric study on propulsion performance of microtubes

Tantos

Valougeorgis

2017

Progress in Flight Physics

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“…Yeh and G. Mattingly [3], Laribi B. and al [4][5][6][7], R. Rans [8], Darin L. and Bowles E. B. [9], F. Sharipov [10] and more recently Laribi B. and al [11] have reported a number of computational studies of installation effects on orifice meter performances.…”

Section: Introductionmentioning

confidence: 99%

Discharge Coefficient Behaviour in Presence of Four Perforated Plates Flow Conditioners

Laribi¹,

Abdellah²

2017

Proceedings of the 4th International Conference of Fluid Flow, Heat and Mass Transfer (FFHMT'17)

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-This paper present a numerical experimentation of the behaviour of the discharge coefficient and the effect of four perforated plates like flow conditioners on the discharge coefficient for flow measurement accuracy. Three of the plates are described by the Standard ISO5167 and the fourth one is proposed for study. The flow is subject to two disturbers namely 50% closed valve and 90° double bend in perpendicular planes. The turbulent flow is examined in conduit with an inner diameter of D=100mm. The diameter of orifice meters are respectively d=50, 60, 70 and 75mm which done for β ratio d/D respectively the values of 0.5, 0.6, 0.7 and 0.75. The orifice meters are located in conduit at different stations z/D downstream the disturbers. The flow is examined with air at Reynolds number Re=2.5x105 . The results showed that the perforated plates have significantly reduced the error on the discharge coefficient. Indeed, the errors recorded downstream disturbers are superior to 12%. Downstream the perforated plates used separately the errors on the discharge coefficient are reduced to a value inferior to 1% for the four plates. It is noted that the standards ISO5167 and AGA3 stipulate that the error on the discharge coefficient Cd must be less than 0.5% for better flow measurement accuracy. By comparing our results with this condition we found that the error obtained on the discharge coefficient with the four perforated plates are substantially reduced especially downstream station z=25D (z =19D downstream disturbers). However the fourth proposed plate with its height porosity produces less lose pressure than those of the other three plates. This is good conditions of exploitation for some installation where height lose pressure are not tolerated.

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“…The same trend appears for small ∆P and large L/R, also leading to small Mach and Reynolds. The low pressure difference value in [149] acts beneficially for this comparison and the maximum error observed here for orifice flow is about 7.7 % at δ = 10. Thus, since the orifice is the most non-linear case, it is expected that this value is the maximum deviation between the two methods forP out /P in ≤ 0.9, δ ≤ 10 and any tube length.…”

Section: Linearized Flowmentioning

confidence: 59%

“…A comparison of the flow rate values with previously obtained DSMC results (P out /P in = 0.9 [149] andP out /P in = 0.7 [152]), reproduced in Table 4.7 modified by the expression…”

Section: Linearized Flowmentioning

confidence: 79%

“…In order to obtain the behaviour of the flow for any rarefaction regime, the most successful approaches rely on the Direct Simulation Monte Carlo (DSMC) method and the discrete velocity method (DVM). For large pressure differences, DSMC has been used in the whole range of rarefaction, due to its simplicity and high accuracy for high speed flows, for the solution of slit [146,147,148], orifice [149,15,150] and short channel flow [151,152,147]. These works have limitations on the pressure ratio range, up to 0.7-0.9 [149,152] due to the increased noise in this regime.…”

Section: Flow Through Channelsmentioning

confidence: 99%

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

Πανταζής¹

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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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Numerical simulation of rarefied gas flow through a thin orifice

Cited by 104 publications

References 36 publications

Parametric study on propulsion performance of microtubes

Parametric study on propulsion performance of microtubes

Discharge Coefficient Behaviour in Presence of Four Perforated Plates Flow Conditioners

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

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