Simulation of gas flow in microchannels with a single bend

Agrawal, Abhishek; Djenidi, L.; Agrawal, Amit

doi:10.1016/j.compfluid.2009.01.004

Cited by 27 publications

(37 citation statements)

References 28 publications

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“…In agreement with the lattice Boltzmann [27] and continuum [28] results, Fig. 12a shows a relative increase of up to 1% in the amount of mass that a channel with a single bend can carry when 0.02 6 Kn in 6 0.08.…”

Section: Dsmc Investigation Of Micro-channels With Bendssupporting

confidence: 72%

“…However, the lattice Boltzmann results in Ref. [27] indicate that the presence of a bend may result in a modest increase in the masscarrying capacity of a micro-channel. To investigate this phenomenon using DSMC, we plot the mass fluxes in Fig.…”

Section: Dsmc Investigation Of Micro-channels With Bendsmentioning

confidence: 99%

“…There is no DSMC data for this kind of geometry in the transition regime, but there is some lattice Boltzmann data [27] that extends into the transition regime, achieving a maximum Knudsen number of 0.286. The geometry considered there is a micro-channel with a single 90-degree bend and a larger aspect ratio than that of [21].…”

Section: Previous Numerical Workmentioning

confidence: 99%

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A DSMC investigation of gas flows in micro-channels with bends

et al. 2013

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This version is available at https://strathprints.strath.ac.uk/42237/ Strathprints is designed to allow users to access the research output of the University of Strathclyde. Unless otherwise explicitly stated on the manuscript, Copyright © and Moral Rights for the papers on this site are retained by the individual authors and/or other copyright owners. Please check the manuscript for details of any other licences that may have been applied. You may not engage in further distribution of the material for any profitmaking activities or any commercial gain. You may freely distribute both the url (https://strathprints.strath.ac.uk/) and the content of this paper for research or private study, educational, or not-for-profit purposes without prior permission or charge.Any correspondence concerning this service should be sent to the Strathprints administrator: strathprints@strath.ac.ukThe Strathprints institutional repository (https://strathprints.strath.ac.uk) is a digital archive of University of Strathclyde research outputs. It has been developed to disseminate open access research outputs, expose data about those outputs, and enable the management and persistent access to Strathclyde's intellectual output.A DSMC investigation of gas flows in micro-channels with bends Monte Carlo (DSMC) solver, and benchmarked against simple micro-channel flow cases found in the literature. DSMC simulations are then carried out of gas flows for varying degrees of rarefaction along micro-channels with both one and two 90-degree bends. The results are compared to those from the equivalent straight micro-channel geometry. Away from the immediate bend regions, the pressure and Mach number profiles do not differ greatly from those in straight channels, indicating that there are no significant losses introduced when a bend is added to a micro-channel geometry. It is found that the inclusion of a bend in a micro-channel can increase the amount of mass that a channel can carry, and that adding a second bend produces a greater mass flux enhancement. This increase happens within a small range of Knudsen number (0.02 6 Kn in 6 0.08). Velocity slip and shear stress profiles at the channel walls are presented for the Knudsen showing the largest mass flux enhancement.

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Section: Dsmc Investigation Of Micro-channels With Bendssupporting

confidence: 72%

Section: Dsmc Investigation Of Micro-channels With Bendsmentioning

confidence: 99%

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A DSMC investigation of gas flows in micro-channels with bends

et al. 2013

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“…This result was obtained separately with DSMC [2], with lattice Boltzmann method [10] and also with continuum fluid 201 dynamic simulation with specialized boundary conditions [11]. Comparing table 3 with figure 9 shows that while the averaged wall shear stress of microchannel with sharp bend is below the corresponding value for straight microchannel, the mass flow rate through the microchannel can be either greater or smaller as compared to that of straight microchannel.…”

Section: Mass Flow Ratementioning

confidence: 87%

Direct simulation Monte Carlo method for gas flows in micro-channels with bends with added curvature

Tisovský

Vít

2017

EPJ Web Conf.

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Abstract. Gas flows in micro-channels are simulated using an open source Direct Simulation Monte Carlo (DSMC) code dsmcFOAM for general application to rarefied gas flow written within the framework of the open source C++ toolbox called OpenFOAM. Aim of this paper is to investigate the flow in micro-channel with bend with added curvature. Results are compared with flows in channel without added curvature and equivalent straight channel. Effects of micro-channel bend was already thoroughly investigated by White et al. Geometry proposed by White is also used here for refference.

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“…In addition, Agrawal et al (2009) and Rovenskaya and Croce (2010), respectively, numerically investigated gas flow in microchannels with a 90°bend and found that the pressure distribution and mass flow rate between the bent and straight long microchannels is nearly identical in the slip regime, and the similarity increases with an increase in Knudsen number. This indicates that the flow is less sensitive to the presence of the bend due to rarefaction effects of the gas and thus furnishes a desirable advantage in the design of microdevices.…”

Section: Introductionmentioning

confidence: 96%

Second-order gaseous slip flow models in long circular and noncircular microchannels and nanochannels

Duan

2011

Microfluid Nanofluid

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This paper significantly extends previous studies to the transition regime by employing the secondorder slip boundary conditions. A simple analytical model with second-order slip boundary conditions for a normalized Poiseuille number is proposed. The model can be applied to either rarefied gas flows or apparent liquid slip flows. The developed simple models can be used to predict the Poiseuille number, mass flow rate, tangential momentum accommodation coefficient, pressure distribution of gaseous flow in noncircular microchannels and nanochannels by the research community for the practical engineering design of microchannels and nanochannels. The developed second-order models are preferable since the difficulty and ''investment'' is negligible compared with the cost of alternative methods such as molecular simulations or solutions of Boltzmann equation. Navier-Stokes equations with second-order slip models can be used to predict quantities of engineering interest such as the Poiseuille number, tangential momentum accommodation coefficient, mass flow rate, pressure distribution, and pressure drop beyond its typically acknowledged limit of application. The appropriate or effective second-order slip coefficients include the contribution of the Knudsen layers in order to capture the complete solution of the Boltzmann equation for the Poiseuille number, mass flow rate, and pressure distribution. It could be reasonable that various researchers proposed different second-order slip coefficients because the values are naturally different in different Knudsen number regimes. It is analytically shown that the Knudsen's minimum can be predicted with the secondorder model and the Knudsen value of the occurrence of Knudsen's minimum depends on inlet and outlet pressure ratio. The compressibility and rarefaction effects on mass flow rate and the curvature of the pressure distribution by employing first-order and second-order slip flow models are analyzed and compared. The condition of linear pressure distribution is given.Keywords Transition regime Á Slip flow Á Second-order model Á Microchannels Á Nanochannels Á Pressure distribution Á Mass flow rate Á Knudsen's minimumSecond-order slip coefficient aMajor semi-axis of ellipse or rectangle (m) aBase width of a trapezoidal, triangular, double-trapezoidal, or rhombic duct (m) bMinor semi-axis of ellipse or rectangle (m) bHeight of a trapezoidal, triangular, double-trapezoidal, or rhombic duct (m) c Short side of a trapezoidal or double-trapezoidal duct (m)Fanning friction factor ¼ sKn Knudsen number ¼ k=D h Kn * Modified Knudsen number = Kn(2 -r)/r L Channel length (m) L Arbitrary length scale _ m Mass flow rate (kg/s) m * Normalized mass flow rate n Correlation parameter P Total wetted perimeter (m) Po Poiseuille number ¼ sL=l " w

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Simulation of gas flow in microchannels with a single bend

Cited by 27 publications

References 28 publications

A DSMC investigation of gas flows in micro-channels with bends

A DSMC investigation of gas flows in micro-channels with bends

Direct simulation Monte Carlo method for gas flows in micro-channels with bends with added curvature

Second-order gaseous slip flow models in long circular and noncircular microchannels and nanochannels

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