Heat transfer enhancement in microchannel heat sink using hybrid technique of ribs and secondary channels

Ghani, Ihsan Ali; Sidik, Nor Azwadi Che; Mamat, R.; Najafi, G.; Asako, Yutaka; Japar, Wan Mohd Arif Aziz

doi:10.1016/j.ijheatmasstransfer.2017.06.103

Cited by 125 publications

(31 citation statements)

References 30 publications

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“…From Eqs. (19) and (20), it can be noted that the Sgen,h depends on Nuave and Re. Increases of Nuave and Re leads to the decreases of C1 and C2 and further the decrease Sgen,h.…”

Section: Entropy Generation Ratementioning

confidence: 99%

“…From Eqs. (20) and (22), the variation of Rth with Nuave and Re can be obtained as shown in Eq (23).…”

Section: Entropy Generation Ratementioning

confidence: 99%

“…Combining the advantages of interrupted microchannel and passive microstructures, Chai et al [13,14] and Wong and Lee [15] introduced the staggered ribs into the transverse microchambers to improve the redeveloping thermal boundary layer. Combining the advantages of streamwise-periodic variations of cross-sectional area and passive microstructures, Xia et al [16,17,18] and Ghani et al [19,20] mounted the rectangular ribs into the microchannels with streamwise-periodically changed cross-sections for further heat transfer augmentation. Furthermore, Sidik et al [21] reviewed the passive techniques for heat transfer augmentation in microchannel heat sink, Ghani et al [22] comprehensively discussed the effect of channel design on the hydrothermal performance of microchannel heat sink, Dewan and Srivastava [23] reviewed the heat transfer enhancement through flow disruption in a microchannel, and Ghani et al [24] comprehensively analyzed the effect of manifold zone parameters on hydrothermal performance of microchannel heat sink.…”

Section: Introductionmentioning

confidence: 99%

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Thermal-hydraulic performance of interrupted microchannel heat sinks with different rib geometries in transverse microchambers

Chai

Wang

2018

International Journal of Thermal Sciences

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The thermal-hydraulic performance of microchannel heat sinks with ribs in the interrupted transverse microchambers is studied using a three-dimensional conjugated heat transfer model and considering entrance effect, viscous heating and temperature-dependent thermophysical properties. Five different configurations of ribs and four lengths along the flow direction for every rib configuration are selected to analyze the effects of rib geometry on the thermal-hydraulic performance. The five rib configurations are rectangular, backward triangular, diamond, forward triangular and ellipsoidal, and the rib geometry parameters include expansion-constriction profile, ratio and length. The effects of rib geometry on thermal-hydraulic performance are firstly examined by the variations of friction factor and Nusselt number with Reynolds number, and corresponding correlations are proposed. Then, the conductive, convective and fluid capacitive thermal resistances are analyzed to obtain some insight into the basic heat transfer mechanism. Next, the entropy generation rates due to heat transfer and fluid friction are investigated for the analysis of the lost available work and irreversibility in the heat transfer process. Finally, the performance evaluation criteria is calculated to comprehensively assess the performance of such interrupted microchannel heat sinks with different rib geometry. For the studied operation parameters and rib geometries, the interrupted microchannel

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“…From Eqs. (19) and (20), it can be noted that the Sgen,h depends on Nuave and Re. Increases of Nuave and Re leads to the decreases of C1 and C2 and further the decrease Sgen,h.…”

Section: Entropy Generation Ratementioning

confidence: 99%

“…From Eqs. (20) and (22), the variation of Rth with Nuave and Re can be obtained as shown in Eq (23).…”

Section: Entropy Generation Ratementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Thermal-hydraulic performance of interrupted microchannel heat sinks with different rib geometries in transverse microchambers

Chai

Wang

2018

International Journal of Thermal Sciences

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“…Zhai et al [120] with triangular and fan-shaped cavities exhibited better performance for triangular cavity with trapezoidal rib for Re in the range of 100-300 and with triangular rib for 300\ Re\600. Ghani et al [121] considered microchannels with rectangular rib (MC-RR), secondary branches (MC-SOC), and both (MC-SOCRR). The highest TEF of 1.98 was obtained for MC-SOCRR through optimization of the geometrical parameter.…”

Section: Authorsmentioning

confidence: 99%

A review of liquid flow and heat transfer in microchannels with emphasis to electronic cooling

2019

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Since the realization of microchannel devices more than three and half decades ago with water as the cooling fluid providing heat transfer enhancement, significant progress has been made to improve the cooling performance. Thermal management for electronic devices with their ever-widening user profile remains the major driving force for performance improvement in terms of miniaturisation, long-term reliability, and ease of maintenance. The ever-increasing requirement of meeting higher heat flux density in more compact and powerful electronic systems calls for further innovative solutions. Some recent studies indicate the promise offered by processes with phase change and the use of active devices. But their adoption for electronic cooling still weighs unfavourably against long-term fluid stability and simplicity of device profile with moderate to high heat transfer capability. Applications and reviews of these promising research trends have been briefly visited in this work. The main focus of this review is the flow and heat transfer regime related to electronic cooling in evolving channel forms, whose fabrication are being enabled by the significant advancement in micro-technologies. Use of disruptive wall structures like ribs, cavities, dimples, protrusions, secondary channels and other interrupts along with smooth-walled channels with curved flow passages remain the two chief geometrical innovations envisaged for these applications. These innovations target higher thermal enhancement factor since this implies more heat transfer capability for the same pumping power in comparison with the corresponding straight-axis, smooth-wall channel configuration. The sophistication necessary to deal with the experimental uncertainties associated with the micron-level characteristic length scale of any microchannel device delayed the availability of results that exhibited acceptable matching with numerical investigations. It is indeed encouraging that the experimental results pertaining to simple smooth channels to grooved, ribbed and curved microchannels without unreasonable increase in pumping power have shown good agreement with conventional numerical analyses based on laminar-flow conjugate heat-transfer model with no-slip boundary condition. The flow mechanism with the different disruptive structures like dimple, cavity and rib, fin and interruption, vortex generator, convergingdiverging side walls or curved axis are reviewed to augment the heat transfer. While the disruptions cause heat transfer enhancement by interrupting the boundary layer growth and promoting mixing by the shed vortices or secondary channel flow, the flow curvature brings in enhancement by the formation of secondary rolls culminating into chaotic advection at higher Reynolds number. Besides these revelations, the numerical studies helped in identifying the parameter ranges, promoting a particular enhancement mechanism. Also, the use of modern tools like Poincare section and the analysis of flow bifurcation leading to chaotic advection is discussed....

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“…The latter was found to have better heat transfer and shorter response time as compared to the former. Ghani et al [11] proposed heat transfer enhancement of a micro-channel heat sink by utilising a hybrid technique of ribs and secondary channels which is closely similar to the oblique fin configuration. They found that a combination of both ribs and secondary channels offered better performance as compared to the case where they were implemented individually.…”

Section: Introductionmentioning

confidence: 99%

Entropy Generation and Heat Transfer Performance in Microchannel Cooling

Kurnia

Lim

Chen

et al. 2019

Entropy

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Owing to its relatively high heat transfer performance and simple configurations, liquid cooling remains the preferred choice for electronic cooling and other applications. In this cooling approach, channel design plays an important role in dictating the cooling performance of the heat sink. Most cooling channel studies evaluate the performance in view of the first thermodynamics aspect. This study is conducted to investigate flow behaviour and heat transfer performance of an incompressible fluid in a cooling channel with oblique fins with regards to first law and second law of thermodynamics. The effect of oblique fin angle and inlet Reynolds number are investigated. In addition, the performance of the cooling channels for different heat fluxes is evaluated. The results indicate that the oblique fin channel with 20° angle yields the highest figure of merit, especially at higher Re (250–1000). The entropy generation is found to be lowest for an oblique fin channel with 90° angle, which is about twice than that of a conventional parallel channel. Increasing Re decreases the entropy generation, while increasing heat flux increases the entropy generation.

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Heat transfer enhancement in microchannel heat sink using hybrid technique of ribs and secondary channels

Cited by 125 publications

References 30 publications

Thermal-hydraulic performance of interrupted microchannel heat sinks with different rib geometries in transverse microchambers

Thermal-hydraulic performance of interrupted microchannel heat sinks with different rib geometries in transverse microchambers

A review of liquid flow and heat transfer in microchannels with emphasis to electronic cooling

Entropy Generation and Heat Transfer Performance in Microchannel Cooling

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