Journal ArticleDOI
Measurements of viscosity, velocity slip coefficients, and tangential momentum accommodation coefficients using a modified spinning rotor gauge
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TLDR
In this paper, a modified spinning rotor gauge (SRG-2; MKS Instruments, Inc.) was used to measure the viscosity, the velocity slip coefficient, and the tangential momentum accommodation coefficient.Abstract:
A selection of experimental viscosity and slip measurements are reported for He and Ar. The measured values have been made with a modified spinning rotor gauge (SRG-2; MKS Instruments, Inc.) where the sphere is coaxially rotated in the cylindrical tube housing. All of the experiments were conducted in the slip regime in accordance with the theory previously developed [S. K. Loyalka, J. Vac. Sci. Technol. A 14, 2940 (1996)]. The theoretical results from this previous article allow one to extract values of the viscosity, the velocity slip coefficient, and the tangential momentum accommodation coefficient from the experimentally obtained angular retardation data for each gas without a need for calibration of the system against a known gas viscosity. Since the existing manufactured SRGs mount horizontally with the rotor angular momentum vector oriented vertically, the required SRG modifications were necessarily limited to the interior of the mounting tube. Here, an insert was developed for the mounting tube in which was bored a short, vertically oriented, cylindrical hole in which the rotor could turn coaxially. Measurements made with this modified version of the SRG are compared with previous experimental results and a discussion of the errors associated with both wall and end effects is included.read more
Citations
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Molecular momentum transport at fluid-solid interfaces in MEMS/NEMS: a review.
TL;DR: This review offers an overview of the major achievements, including experiments, theories and molecular dynamics simulations, in the field with particular emphasis on the effects on microfluidics and nanofluidics in nanoscience and nanotechnology.
Journal ArticleDOI
Expressions for the Evaporation and Condensation Coefficients in the Hertz-Knudsen Relation.
Aaron H. Persad,C. A. Ward +1 more
TL;DR: It is shown how seemingly small simplifications, such as assuming thermal equilibrium across the liquid-vapor interface during evaporation, can lead to the erroneous predictions from the HK relation that have been reported in the literature.
Journal ArticleDOI
Survey on measurement of tangential momentum accommodation coefficient
Amit Agrawal,S.V. Prabhu +1 more
TL;DR: The tangential momentum accommodation coefficient (TMAC) as discussed by the authors is the boundary condition for flow of gases in the slip and transition flow regimes, and its precise determination is important for several other applications as well.
Journal ArticleDOI
Data on the Velocity Slip and Temperature Jump on a Gas-Solid Interface
TL;DR: In this article, the velocity slip and temperature jump coefficients have been applied to modeling of gas flows and a critical analysis of theoretical and experimental data available in the open literature is presented in an accessible form so that it can be easily understandable for nonspecialists in rarefied gas dynamics.
Journal ArticleDOI
Molecular Simulations of Knudsen Wall-slip: Effect of Wall Morphology
TL;DR: In this article, a molecular simulation study of the phenomena of wall slip occurring in rarefied gases flowing through micro- and nano-channels is presented, where noninteracting gas molecules are bombarded at an atomic wall composed of rigid atoms with suitably distributed velocities.
References
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Journal ArticleDOI
Equilibrium and transport properties of the noble gases and their mixtures at low density
TL;DR: In this article, a set of easy-to-program expressions for the calculation of the thermodynamic and transport properties of the five noble gases (He, Ne, Ar, Kr, Xe) and of the 26 binary and multicomponent mixtures that can be formed with them are presented.
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Coefficients of Slip in Gases and the Law of Reflection of Molecules from the Surfaces of Solids and Liquids
TL;DR: In this paper, the Stokes' law was modified by the factor (1+Al / a), where l / a is the ratio of mean free path to radius of droplet, and xi is the coefficient of slip between gases and solids.
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An absolute determination of the viscosity of eleven gases over a range of pressures
J. Kestin,W. Leidenfrost +1 more
TL;DR: The measurements described in this article were based on a new theory of the oscillating-disk viscometer which includes the effect of the finite radius as well as that of its cylindrical circumference.
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Viscosity of Nitrogen, Helium, Neon, and Argon from —78.5° to 100°C below 200 Atmospheres
TL;DR: In this article, a new capillary-flow viscometer was developed for the measurement of the absolute viscosity of gases as a function of temperature and pressure, and the experimental results are believed to be accurate within 0.1%.
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Temperature jump and thermal creep slip: Rigid sphere gas
TL;DR: In this paper, the half-space problems of temprature jump and thermal creep slip were solved for a rigid sphere gas based on the linearized Boltzmann equation using the SN method, and it was shown that accurate results for the jump/slip coefficients and the temperature, density, and velocity can be obtained in relatively short computational times.