Numerical computation of fluid flow and heat transfer in microchannels

Toh, K.C.; Chen, X.Y.; Chai, John C.

doi:10.1016/s0017-9310(02)00223-5

Cited by 229 publications

(82 citation statements)

References 8 publications

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“…Hence, the variation of the thermophysical properties along the channel could sometimes explain the apparent deviations of the microchannel flow and heat transfer [27]. Herwig and Mahulikar [28] …”

Section: Temperature Dependent Propertiesmentioning

confidence: 99%

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Single-phase heat transfer in microchannels: The importance of scaling effects

Rosa

Karayiannis

Collins

2009

Applied Thermal Engineering

254

117

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Microscale single-phase heat transfer is widely used in industrial and scientific applications and for this reason, many related papers have been published in the last two decades. Nevertheless, inconsistencies between published results still exist and there is no generally accepted model for the prediction of singlephase heat transfer in microchannels. This paper presents a review of the experimental and numerical results available in the open literature. Heat transfer in microchannels can be suitably described by standard theory and correlations, but scaling effects (entrance effects, conjugate heat transfer, viscous heating, electric double layer (EDL) effects, temperature dependent properties, surface roughness, rarefaction and compressibility effects), often negligible in macro-channels, may now have a significant influence and have to be accounted for. Furthermore, measurement uncertainties may be more important, due to the reduced characteristic dimensions, so have to be accurately checked and, where possible, reduced. Experiments with single channels are more accurate and in good agreement with predictions from published correlations, in contrast to multi-(parallel) channel experiments. The latter are subject to maldistribution, 3D conjugate heat transfer effects and larger measurement uncertainties. Sub-continuum mathematical models for fluid dynamics are briefly reviewed and explained. These models are expected to gain a growing interest in the near future due to the rapid descent of microchannel dimensions down to the nano-scale. The paper concludes with a concise set of recommendations for purposes of performance and design. For single channels, available correlations for macro-channels can also give reliable predictions at the micro-scale, but only if all the scaling effects can be considered negligible. Otherwise, when scaling effects cannot be neglected or for the case of heat exchangers with parallel channels, suitable numerical simulations may be the sole alternative to carefully designed experiments to evaluate the heat transfer rates. KeywordsMicrochannels, scaling effects, measurement uncertainties, sub-continuum effects.

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Section: Temperature Dependent Propertiesmentioning

confidence: 99%

“…Moreover, these correlations can be used for different cross section geometries and boundary conditions. Equations (24)(25), (26) and (27) give the correlations of Gnielinski [57], Dittus and Boelter [61] and Pethukov et al [62], respectively.…”

Section: Measurement Uncertaintiesmentioning

confidence: 99%

Single-phase heat transfer in microchannels: The importance of scaling effects

Rosa

Karayiannis

Collins

2009

Applied Thermal Engineering

254

117

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“…In relation to microscale heat transfer, some researchers have reported results obtained for the Nusselt number in good agreement with the classical theory [25,[30][31][32][33]. However, other researchers have indicated that differences in rates and coefficients of heat transfer, as well as in Nusselt number, can be related to the flow velocity and fluid temperature [16,[34][35][36], the Reynolds number [9], the heat transfer conjugated [2,[37][38][39], the viscous dissipation [16,20,26,40,41], the surface roughness [42], the aspect ratio of microchannels [5,43] and the conductivity of the material that compose them [2,[37][38][39], besides experimental uncertainties [4,[30][31][32][33]44].…”

Section: Introductionmentioning

confidence: 59%

“…A lot of experimental studies [1,2,[5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21], besides theoretical [22][23][24] and numerical studies [5,[25][26][27][28], have been carried out, in the past decades, seeking to investigate the hydrodynamics and heat transfer characteristics in microscale. The results obtained in several of these studies show diversions among themselves and, also, with the conventional theory.…”

Section: Introductionmentioning

confidence: 99%

Numerical Analysis About the Influence of Inappropriate Shape of the Cross-Section of Microchannels in Laminar Flow

Hollweg¹,

Oliveski²,

Corte³

2013

Proceedings of the 3rd South-East European Conference on Computational Mechanics – SEECCM III

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“…For more than a decade this drive has resulted in a significant amount of research being done in the field of micro-channels and micro-channel materials [2][3][4][5] in order to maximise the heat transfer density rate. More recently, researchers have become interested in the use of nanofluids as working fluids in micro-channel cooling, a technique that has yielded successful results [6][7][8].…”

Section: Introductionmentioning

confidence: 99%

Maximum thermal conductance for a micro-channel, utilising Newtonian and non-Newtonian fluid

2014

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This paper investigates the thermal behaviour of two micro-channel elements cooled by Newtonian and non-Newtonian fluids, with the objective to maximise thermal conductance subject to constraints. This is done firstly for a two-dimensional duct micro-channel and secondly for a three-dimensional complex micro-channel. A numerical model is used to solve the governing equations relating to flow and temperature fields for both cases.

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Numerical computation of fluid flow and heat transfer in microchannels

Cited by 229 publications

References 8 publications

Single-phase heat transfer in microchannels: The importance of scaling effects

Single-phase heat transfer in microchannels: The importance of scaling effects

Numerical Analysis About the Influence of Inappropriate Shape of the Cross-Section of Microchannels in Laminar Flow

Maximum thermal conductance for a micro-channel, utilising Newtonian and non-Newtonian fluid

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