Gas separation by means of the Knudsen compressor

Takata, Shigeru; Sugimoto, Hiroshi; Kosuge, Shingo

doi:10.1016/j.euromechflu.2006.05.002

Cited by 63 publications

(64 citation statements)

References 33 publications

(57 reference statements)

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“…However, we mention that an extension of [1] to the Boltzmann and the full BGK models can be found in [4]. This approach has also been applied to gaseous mixtures [44]. Third, our diffusion model is used for various numerical simulations and our approach is validated by comparisons with full kinetic simulations.…”

Section: Introductionmentioning

confidence: 99%

A Diffusion Model for Rarefied Flows in Curved Channels

Aoki¹,

Degond²,

Mieussens³

et al. 2008

Multiscale Model. Simul.

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Abstract. In this paper, we derive a one-dimensional convection-diffusion model for a rarefied gas flow in a two-dimensional curved channel on the basis of the Boltzmann (BGK) model. The flow is driven by the temperature gradient along the channel walls, which is known as the thermal creep phenomenon. This device can be used as a micro-pumping system without any moving part. Our derivation is based on the asymptotic technique of the diffusion approximation. It gives a macroscopic (fluid) approximation of the microscopic (kinetic) equation. We also derive the connection conditions at the junction where the curvature is not continuous. The pumping device is simulated by using a numerical approximation of our convection-diffusion model which turns to agree very well with full two dimensional kinetic simulations. It is then used to obtain very fast computations on long pumping devices, while the computational cost of full kinetic computations is still nowadays prohibitive for such cases.

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Section: Introductionmentioning

confidence: 99%

A Diffusion Model for Rarefied Flows in Curved Channels

Aoki¹,

Degond²,

Mieussens³

et al. 2008

Multiscale Model. Simul.

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“…The separation effect is very important in many applications including pumping, sampling, filtering, etc. Takata et al 2007;Sugimoto 2009) and should be taken into consideration in the estimation of the mass flow rate. A detailed investigation of the separation effect has been presented in Sharipov and Kalempa (2005) for binary gas flow through long tubes into vacuum, based on the prescribed number densities of the two reservoirs.…”

Section: Separation Effect In Rarefied Binary Gaseous Flowmentioning

confidence: 99%

“…The light particles are traveling faster than the heavier ones resulting to the change of the concentration of the gas mixture as it flows along the channel. This situation, known as the separation effect, must be taken into account in simulations and may be useful in the design of gaseous microsystems Takata et al 2007;Sugimoto 2009).…”

Section: Introductionmentioning

confidence: 99%

Rarefied gas flow of binary mixtures through long channels with triangular and trapezoidal cross sections

Szalmás

Valougeorgis

2010

Microfluid Nanofluid

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The flow of binary gas mixtures through long micro-channels with triangular and trapezoidal cross sections is investigated in the whole range of the Knudsen number. The flow is driven by pressure and concentration gradients. The McCormack kinetic model is utilized to simulate the rarefied flow of the gas mixture, and the kinetic equations are solved by an upgraded discrete velocity algorithm. The kinetic dimensionless flow rates are tabulated for selected noble gas mixtures flowing through micro-channels etched by KOH in silicon (triangular and trapezoidal channels with acute angle of 54.74°). Furthermore, the complete procedure to obtain the mass flow rate for a gas mixture flowing through a channel, based on the dimensionless kinetic results, which are valid in each cross section of the channel, is presented. The study includes the effect of the separation phenomenon. It is shown that gas separation may change significantly the estimated mass flow rate. The presented methodology can be used for engineering purposes and for the accurate comparison with experimental results.

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“…The system is periodic in the axial (flow) direction (T(x, y) = T(x + 2L, y), etc.). Knudsen compressors are devices with no moving parts, which exploit the kinetic phenomenon of thermal transpiration-the tendency of a rarefied (Kn > 0) gas in contact with a wall along which a temperature gradient exists to move from cold regions to hot regions [46]-to pump or compress a gas and more recently to separate gases [54]. These devices generally consist of many stages, each with a capillary section (x < L in the figure) with a positive streamwise temperature gradient, followed by a connector section (x > L in the figure) with a negative temperature gradient.…”

Section: (B) Applicationsmentioning

confidence: 99%

On efficient simulations of multiscale kinetic transport

Radtke

Péraud

Hadjiconstantinou

2013

Phil. Trans. R. Soc. A.

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We discuss a new class of approaches for simulating multiscale kinetic problems, with particular emphasis on applications related to small-scale transport. These approaches are based on a decomposition of the kinetic description into an equilibrium part, which is described deterministically (analytically or numerically), and the remainder, which is described using a particle simulation method. We show that it is possible to derive evolution equations for the two parts from the governing kinetic equation, leading to a decomposition that is dynamically and automatically adaptive, and a multiscale method that seamlessly bridges the two descriptions without introducing any approximation . Our discussion pays particular attention to stochastic particle simulation methods that are typically used to simulate kinetic phenomena; in this context, these decomposition approaches can be thought of as control-variate variance-reduction formulations, with the nearby equilibrium serving as the control. Such formulations can provide substantial computational benefits in a broad spectrum of applications because a number of transport processes and phenomena of practical interest correspond to perturbations from nearby equilibrium distributions. In many cases, the computational cost reduction is sufficiently large to enable otherwise intractable simulations.

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Gas separation by means of the Knudsen compressor

Cited by 63 publications

References 33 publications

A Diffusion Model for Rarefied Flows in Curved Channels

A Diffusion Model for Rarefied Flows in Curved Channels

Rarefied gas flow of binary mixtures through long channels with triangular and trapezoidal cross sections

On efficient simulations of multiscale kinetic transport

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