The experimental investigation of axial heat conduction effect on the heat transfer analysis in microchannel flow

Huang, Chih-Yung; Wu, C.C.; Chen, Ying-Nung; Liou, Tong‐Miin

doi:10.1016/j.ijheatmasstransfer.2013.10.059

Cited by 40 publications

(14 citation statements)

References 13 publications

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“…20 HEX, heat exchangers [Color figure can be viewed at wileyonlinelibrary.com] F I G U R E 2 A simple structure of MCHS: (A) stacked model and (B) computational domain. 13 MCHS, microchannel heat sinks conduction, 2,46,47 aspect ratio, 27,48,49 and viscous dissipation 2,50 are addressed as the possible reasons for the deviation from classical theory.…”

Section: Axial Heat T a B L E 1 Classification Of Heat Exchangers (Hementioning

confidence: 99%

A review of heat and fluid flow characteristics in microchannel heat sinks

Çetkin

2020

Heat Trans

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Heat transfer and flow characteristic in microchannel heat sinks (MCHS) are extensively studied in the literature due to high heat transfer rate capability by increased heat transfer surface area relative to the macroscale heat sinks. However, heat transfer and fluid flow characteristics in MCHS differ from conventional ones because of the scaling effects. This review summarizes the studies that are mainly based on heat transfer and fluid flow characteristic in MCHS. There is no consistency among the published results; however, everyone agrees on that there is no new physical phenomenon in microscale that does not exist at macroscale. Only difference between them is that the effect of some physical phenomena such as viscous dissipation, axial heat conduction, entrance effect, rarefaction, and so forth, is negligibly small at macroscale, whereas it is not at microscale. The effect of these physical phenomena on the heat transfer and flow characteristics becomes significant with respect to specified conditions such as Reynolds number, Peclet number, hydraulic diameter, and heat transfer boundary conditions. Here, the literature was reviewed to document when these physical phenomena become significant and insignificant.

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Section: Axial Heat T a B L E 1 Classification Of Heat Exchangers (Hementioning

confidence: 99%

A review of heat and fluid flow characteristics in microchannel heat sinks

Çetkin

2020

Heat Trans

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“…However, most analyses of experimental investigations consider linear variation, thus arriving at wrong conclusions. To overcome this experimental difficulty, Huang et al [18] used molecule-based temperature sensors in their experimental investigation to study the effect of axial heat conduction on the heat transfer analysis in microchannel flow. Rhodamine B/DI water and Ru(bpy)/dope have been respectively applied as temperaturesensitive fluid and temperature-sensitive paint for fluid and surface temperature measurements.…”

Section: Axial Back Conduction In Micro-sized Channelsmentioning

confidence: 99%

Axial Back Conduction through Channel Walls During Internal Convective Microchannel Flows

Khandekar

Moharana

2015

Springer Tracts in Mechanical Engineering

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Recent developments during the last decade in the field of manufacturing and development of many high-power mini-/micro-devices led to increased interest in microfluidic devices involving heat transfer. Since the pioneering work by Tuckerman and Pease (IEEE Electron Device Lett 2:126-129, 1981) on the use of microchannels for high heat flux removal, certainly a lot of developments has been witnessed through ever-increasing analytical, experimental, and highly sophisticated numerical studies by many researchers across the globe. In spite of this progress, many fundamental understandings of flow and heat transfer phenomena in mini-/microchannel systems are still obscure. One such phenomenon is the flow of heat in the solid wall of microchannel systems by means of conduction normally in a direction opposite to that of internal convective mini-/microchannel flow of fluid, called "axial wall conduction" or "axial back conduction." Axial back conduction is not a new phenomenon, rather mostly neglected unintentionally because of its convincingly smaller influence on heat transfer in conventional-size channels. As the hydraulic diameter of a channel decreases, the coupling between the substrate and bulk fluid temperatures becomes significant because of the relative size of the fluid to the solid wall. Unlike in conventional-size channels, negligence of axial back conduction along the solid walls of micro heat exchangers frequently leads to erroneous conclusions and inconsistencies in the interpretation of transport data. Thus, it is important to explicitly identify the thermofluidic parameters of interest which lead to a distortion in the boundary conditions and thus the true estimation of species transfer coefficients. In this chapter, we focus our attention on the axial back conduction in the solid substrate/channel wall as against the axial back conduction in the liquid flow domain; thus, a detailed review of the state-of-the-art on axial back conduction in both conventional as well as mini-/microchannel systems is presented.

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“…Specifically, rarefaction and axial conduction for fully developed flows in microchannels studied by Hadjiconstantinou and Simek [15] where fully developed Nu values found to be increasing by axial conduction. 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).…”

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

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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.

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The experimental investigation of axial heat conduction effect on the heat transfer analysis in microchannel flow

Cited by 40 publications

References 13 publications

A review of heat and fluid flow characteristics in microchannel heat sinks

A review of heat and fluid flow characteristics in microchannel heat sinks

Axial Back Conduction through Channel Walls During Internal Convective Microchannel Flows

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

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