Extended Graetz problem including streamwise conduction and viscous dissipation in microchannel

Jeong, Haeseong; Jeong, Jae–Tack

doi:10.1016/j.ijheatmasstransfer.2005.11.026

Cited by 107 publications

(81 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…When the heat is uniformly supplied to the fluid through the walls, increasing Br caused a decrease in Nu. Again, this behaviour agreed with that reported by Jeong and Jeong [36].…”

Section: Viscous Heatingsupporting

confidence: 92%

“…The papers of Jeong and Jeong [36], Chen [35], and Tunc and Bayazitoglu [38] have already been introduced in Section 2.3. They also analyzed viscous heating effects.…”

Section: Viscous Heatingmentioning

confidence: 99%

“…Fig. 6, from Jeong and Jeong [36], shows the effects of viscous heating on the local Nusselt number, for Kn = 0 (i.e. no rarefaction effects) and Pe = 10 6 (i.e.…”

Section: Viscous Heatingmentioning

confidence: 99%

See 2 more Smart Citations

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

Rosa

Karayiannis

Collins

2009

Applied Thermal Engineering

249

117

View full text Add to dashboard Cite

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.

show abstract

“…When the heat is uniformly supplied to the fluid through the walls, increasing Br caused a decrease in Nu. Again, this behaviour agreed with that reported by Jeong and Jeong [36].…”

Section: Viscous Heatingsupporting

confidence: 92%

“…The papers of Jeong and Jeong [36], Chen [35], and Tunc and Bayazitoglu [38] have already been introduced in Section 2.3. They also analyzed viscous heating effects.…”

Section: Viscous Heatingmentioning

confidence: 99%

See 1 more Smart Citation

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

Rosa

Karayiannis

Collins

2009

Applied Thermal Engineering

249

117

View full text Add to dashboard Cite

show abstract

“…Decrease of Nu fd is more profound with the increase of rarefaction for a viscous heating case. Our finding showed good agreement with Ref [19].…”

Section: Resultssupporting

confidence: 93%

“…Rarefaction and axial conduction were also studied for thermally developing region by Huang et al [16], Kakac et al [17] and Cole et al [18] where axial conduction was found to increase the temperature at the entrance of the channel and enhance the heat transfer. Jeong and Jeong [19], Koo and Kleinstreuer [20] and Chen [21] studied viscous effects with rarefaction and reported that fully developed Nusselt number increases under viscous dissipation in the presence of small Knudsen numbers (slip flow 0.01 < Kn < 0.1). Similarly, Cetin et al [8,22] focused to extend the Graetz problem by including all three micro-scale effects.…”

Section: Introductionmentioning

confidence: 99%

The extended Graetz problem for micro-slit geometries; analytical coupling of rarefaction, axial conduction and viscous dissipation

Kalyoncu

Barışık

2016

International Journal of Thermal Sciences

View full text Add to dashboard Cite

a b s t r a c tIn order to support the recent MEMS and Lab-on-a-chip technologies, we studied heat transport in micro-scale slit channel gas flows. Since the micro convection transport phenomena diverges from conventional macro-scale transport due to rarefaction, axial conduction and viscous heating, an accurate understanding requires a complete coupling of these effects. For such cases, we studied heat transfer in hydrodynamically developed, thermally developing gas flows in micro-slits at various flow conditions. The analytical solution of the energy equation considered both the heat conduction in the axial direction and heat dissipation of viscous forces. Furthermore, updated boundary conditions of velocity slip and temperature jump were applied based on Knudsen number of flow in order to account for the nonequilibrium gas dynamics. Local Nusselt number (Nu) values were calculated as a function of Peclet (Pe), Knudsen (Kn) and Brinkman (Br) numbers which were selected carefully according to possible micro-flow cases. Strong variation of Nu in thermal development length was found to dominate heat transfer behavior of micro-slits with short heating lengths for early slip flow regime. For this instance, influence of axial conduction and viscous dissipation was equally important. On the other hand, high Kn slip flow suppressed the axial conduction while viscous heating in a small surface-gas temperature difference case mostly determined the fully developed Nu and average heat transfer behavior as a function of Kn value.

show abstract

Thermal Applications of Microchannel Flows

Narayanan

Liburdy

Pence

2013

Encyclopedia of Aerospace Engineering

View full text Add to dashboard Cite

There are several applications wherein high‐heat‐flux thermal transport is crucial to the reliable operation of devices, to increased efficiency of processes, and for miniaturization. Heat transport through microchannels provides an attractive method of removing such high heat fluxes. This chapter describes the basic theory of microchannel fluid flow and heat transport illustrating the distinct advantages of this technology for several process intensification applications, including those related to the aerospace industry. The state of current knowledge in single‐phase and phase‐change flows in microchannels is provided with an emphasis on the differences between thermal transport in conventional sized channels and microchannels. Practical considerations such as mitigation of flow maldistribution and/or flow oscillations and fabrication are also addressed. Several examples of use of microchannel technology in heat and mass transfer are provided.

show abstract

Extended Graetz problem including streamwise conduction and viscous dissipation in microchannel

Cited by 107 publications

References 11 publications

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

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

The extended Graetz problem for micro-slit geometries; analytical coupling of rarefaction, axial conduction and viscous dissipation

Thermal Applications of Microchannel Flows

Contact Info

Product

Resources

About