The role of microchannel geometry selection on heat transfer enhancement in heat sinks: A review

Dash, Binayak; Nanda, J.; Rout, Sachindra Kumar

doi:10.1002/htj.22357

Cited by 19 publications

(5 citation statements)

References 125 publications

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“…Global Nusselt number dependency on Re, TR and AR is shown in Figure 4. It can be observed that dependency of the global Nusselt number with Reynolds number follows approximately a linear trend for the studied region, which is in accordance with the correlations shown in [28] for rectangular microchannels in laminar flow. Given the same Reynolds, left Figure 4 shows that increments of the tip clearance ratio TR diminish both the overall Nusselt number and the slope of the Nu − Re curve.…”

Section: Resultssupporting

confidence: 89%

Impact of Channels Aspect Ratio on the Heat Transfer in Finned Heat Sinks with Tip Clearance

et al. 2022

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A 3D numerical study is used to analyze the flow topology and performance, in terms of heat transfer efficiency and required pumping power, of heat sink devices with different channel aspect-ratio in the presence of tip-clearance. Seven different channel aspect ratios AR, from 0.25 to 1.75, were analyzed. The flow Reynolds numbers Re, based on the average velocity evaluated in the device channels region, were in the range of 200 to 1000. Two different behaviors of the global Nusselt were obtained depending on the flow Reynolds number: for Re<600, the heat transfer increased with the channels aspect ratio, e.g., for Re=400, the global Nusselt number increased by 14% for configuration AR=1.75 when compared to configuration AR=0.25. For Re>600, the maximum Nusselt is obtained for the squared-channel configuration, and, for some configurations, flow destabilization to a unsteady regime appeared. For Re=700, Nusselt number reduced when compared with the squared-channel device, 11% and 2% for configurations with AR=0.25 and 1.75, respectively. Dimensionless pressure drop decreased with the aspect ratio for all cases. In the context of micro-devices, where the Reynolds number is small, these results indicate that the use of channels with high aspect-ratios is more beneficial, both in terms of thermal and dynamic efficiency.

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Section: Resultssupporting

confidence: 89%

Impact of Channels Aspect Ratio on the Heat Transfer in Finned Heat Sinks with Tip Clearance

et al. 2022

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“…This is mainly influenced by: (1) The extended fins on the windward side catch a lot of frost. (2) The fins extending on the windward side make the heat exchanger frosting more uniform. The overall frost accumulation of MCHX-A is 10.3-46.9% higher than that of MCHX-B under different frosting conditions.…”

Section: Pressure Drop Analysismentioning

confidence: 99%

“…Under the background of carbon peaking and carbon neutrality, the application of microchannel heat exchangers (MCHXs) in refrigeration and heat pump systems has become a research hotspot. Compared with the conventional fin-and-tube heat exchanger (FTHX), the MCHX has the advantages of higher heat transfer efficiency [1,2], less refrigerant charging [3], and lower cost [4,5]. However, when the MCHX works in the winter, the frost will form and accumulate faster on the fin surface [6,7], which will lead to a decrease in airflow rate and an increase in the thermal resistance, thus reducing the heating capacities of the heat pump units [8][9][10].…”

Section: Introductionmentioning

confidence: 99%

Performance Improvement of Microchannel Heat Exchangers with Modified Louver Fins under Frosting Conditions

2023

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Microchannel heat exchangers (MCHX) are increasingly being used in refrigeration and heat pumps due to their superior thermal-hydraulic properties. However, when the MCHX surface temperature drops below the freezing point, frost will accumulate on the fin surface, which significantly affects the heat transfer performance. In this study, a modified MCHX with extended windward fins was developed to improve the frosting performance. The thermal-hydraulic performance of the modified MCHX and conventional MCHX were compared and evaluated under frosting conditions. Results show that the extended fins on the windward side capture a large amount of frost and delay the rapid blockage of air flow passage by frost. The modified MCHX structure makes the frost more evenly distributed. During the 60 min frosting cycle, the total heat transfer capacity and the mass of the accumulated frost of the modified MCHX are 9.6–49.7% and 10.3–46.9% higher than the conventional MCHX, respectively. Furthermore, the modified MCHX has greater potential to improve the thermal-hydraulic performance under the condition of more uneven frost layer distribution. The purpose of this work is to provide useful guidance for the optimal design of MCHX under frosting conditions.

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“…Kandlikar and Grande have offered a thorough historical perspective on the evolution of microchannels and mini-channels 49) . According to current research, microchannels can be categorized based on a number of factors, including the Knudsen number (Kn) [49][50][51][52][53][54][55][56][57] . All in all, the comprehensive review works along with recent insights agree that geometry is of utmost concern in the design of microchannels in terms of controlling fluid flow parameters by modifying geometry considerations [58][59][60] .…”

Section: Classification Of Microchannelsmentioning

confidence: 99%

A Review on Microchannel Fabrication Methods and Applications in Large-Scale and Prospective Industries

Afzal¹,

Tayyaba²,

Ashraf³

et al. 2022

Evergreen

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Microchannels based on microelectromechanical systems (MEMS) have received a lot of interest in the microfluidics and biomedical fields over the past forty years. While their applications have been multifarious, a comprehensive literature review focusing on their design, type, and applications is not currently present in the literature. Researchers working on these elements of microchannels will gain targeted knowledge from the current review on microchannels. Due to its advanced properties, flexibility of mass, and small size, microdevice demand has been rising quickly, particularly in industrial applications. The classification of microchannels and their uses are the main focus of this work. These include but are not limited to molding, electroplating, lithography, lab-ona-chip, micromolding, micromachining, micromilling, laser ablation, lithography, microcontact printing (µcp), hot embossing, electrochemical micromachining (EMM), and etching. In addition, numerous hybrid techniques for microchannel manufacturing have been reported. So, in essence, this review offers a range of advancements in microchannel manufacturing. The review also attempts to present a qualitative analysis describing the various methodologies associated with microchannels in terms of their design, shape, and flow regimes for applications such as pressure drop and transfer of heat prediction. Additionally, depending on the precise uses needed, a number of materials, including but not limited to ceramics, silicon, metals, and polymers, are utilized in the manufacture of microchannels. On metallic substrates, polymers such as silicon, glass, and polymeric materials are used. The biomedical industry uses polymeric and glass substrates instead of silicon substrates, which are used for mechanical engineering and electronic applications. In addition to outlining methods for choosing the best kind of microchannel, this paper also suggests important directions for the future.

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The role of microchannel geometry selection on heat transfer enhancement in heat sinks: A review

Cited by 19 publications

References 125 publications

Impact of Channels Aspect Ratio on the Heat Transfer in Finned Heat Sinks with Tip Clearance

Impact of Channels Aspect Ratio on the Heat Transfer in Finned Heat Sinks with Tip Clearance

Performance Improvement of Microchannel Heat Exchangers with Modified Louver Fins under Frosting Conditions

A Review on Microchannel Fabrication Methods and Applications in Large-Scale and Prospective Industries

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