Effects of Knudsen number and geometry on gaseous flow and heat transfer in a constricted microchannel

Shokouhmand, Hossein; Bigham, Sajjad; Isfahani, Rasool Nasr

doi:10.1007/s00231-010-0674-7

Cited by 13 publications

(6 citation statements)

References 21 publications

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“…Developing slip flow CWT heat transfer in wavy or constricted microchannels is analyzed in Refs. [91] and [92], respectively. The boundary conditions (4) and (11) take into account the thermal creep and significant viscous dissipation effects are observed.…”

Section: Microchannels With Other Kinds Of Cross-sectionsmentioning

confidence: 99%

Gas Microflows in the Slip Flow Regime: A Critical Review on Convective Heat Transfer

Colin

2011

Journal of Heat Transfer

131

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Accurate modeling of gas microvection is crucial for a lot of MEMS applications (microheat exchangers, pressure gauges, fluidic microactuators for active control of aerodynamic flows, mass flow and temperature microsensors, micropumps, and microsystems for mixing or separation for local gas analysis, mass spectrometers, vacuum, and dosing valves…). Gas flows in microsystems are often in the slip flow regime, characterized by a moderate rarefaction with a Knudsen number of the order of 10 À2 -10 À1 . In this regime, velocity slip and temperature jump at the walls play a major role in heat transfer. This paper presents a state of the art review on convective heat transfer in microchannels, focusing on rarefaction effects in the slip flow regime. Analytical and numerical models are compared for various microchannel geometries and heat transfer conditions (constant heat flux or constant wall temperature). The validity of simplifying assumptions is detailed and the role played by the kind of velocity slip and temperature jump boundary conditions is shown. The influence of specific effects, such as viscous dissipation, axial conduction and variable fluid properties is also discussed.

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Section: Microchannels With Other Kinds Of Cross-sectionsmentioning

confidence: 99%

Gas Microflows in the Slip Flow Regime: A Critical Review on Convective Heat Transfer

Colin

2011

Journal of Heat Transfer

131

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“…Kn 1), either variable cross-section or a straight one, will be choked because of the occurrence of the sonic point, at the throat position for the variable cross-section nozzle or at the center of exit for the straight channel [31]. However, experimental studies have demonstrated that gas flows driven by a pressure difference through microchannels behave differently from such classical theories [6,17,24,32]. For micro-nozzles with variable cross sections, once the gas flow is choked, the sonic point moves backwards from the throat due to the higher viscous dissipation at smaller cross section [6].…”

Section: Introductionmentioning

confidence: 99%

“…Therefore, a better and accurate understanding of the mechanisms of gas flow and heat transfer in microchannels and nanochannels is very important and critical for design and analysis of micro-and nanosystems [3,4]. The previous studies have reported some special characteristics of gas flow and heat transfer in micro-and nanochannels at high Knudsen number [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29]. When the gas density is sufficiently low so that it can be treated as ideal gas, the micro gas flow shows similar behaviors as rarefied gas, including flow slip and temperature jump on surfaces [30]; if the gas is so dense however that the assumption of ideal gas breaks down, the non-ideal gas effect will influence the flow resistance and heat transfer on surfaces [16,22].…”

Section: Introductionmentioning

confidence: 99%

On mechanisms of choked gas flows in microchannels

Shan

Wang

2015

Physics Letters A

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“…They investigated the e ects of back pressure, Knudsen number, and gassurface interaction on the nozzle ow behavior by the compressible OpenFOAM solver. Shokouhmand and Bigham [19] analyzed both the hydrodynamic and thermal aspects of a gaseous ow in the constricted microchannels.…”

Section: Introductionmentioning

confidence: 99%

Investigation of fluid flow and heat transfer of compressible flow in a constricted microchannel

Heydari

2016

Scientia Iranica

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Heat transfer and hydrodynamics of air ow in a constricted microchannel are numerically investigated by considering the e ect of geometry, stagnation pressure and temperature at the inlet, and applied heat ux at the walls. Kurganov-Tudmor method is used to solve the governing equation; Maxwell and Smoluchowski approaches are used to model the rarefaction e ects of compressible micro ow. This study shows that using slip model is necessary in both high-speed and low-speed ows, especially at the downstream of the constricted portion. Also, throat height reduction results in more rarefaction and compressibility at the constricted region.

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Effects of Knudsen number and geometry on gaseous flow and heat transfer in a constricted microchannel

Cited by 13 publications

References 21 publications

Gas Microflows in the Slip Flow Regime: A Critical Review on Convective Heat Transfer

Gas Microflows in the Slip Flow Regime: A Critical Review on Convective Heat Transfer

On mechanisms of choked gas flows in microchannels

Investigation of fluid flow and heat transfer of compressible flow in a constricted microchannel

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