Effects of surface roughness in microchannel with passive heat transfer enhancement structures

Lu, Hui; Xu, Minghai; Gong, Liang; Duan, Xiaoyang; Chai, John C.

doi:10.1016/j.ijheatmasstransfer.2019.119070

Cited by 37 publications

(11 citation statements)

References 27 publications

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“…It is worth mentioning here that the combination of more than one passive methods in a microchannel design can improve or negatively affect the overall performance of MCHS. According to Lu et al [113], the effect surface roughness of three different microchannel designs, namely wavy, dimpled, and square channels on hydrothermal performance, was highly dependent on the local flow field in each design. The surface roughness has a less impact on the dimpled and valley of the wavy channel because of low-velocity area present close to the wall.…”

Section: Mchs With Hybrid Passive Methodsmentioning

confidence: 99%

A review of passive methods in microchannel heat sink application through advanced geometric structure and nanofluids: Current advancements and challenges

Japar

Sidik

Saidur

et al. 2020

Nanotechnology Reviews

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Microchannel heat sink (MCHS) is an advanced cooling technique to fulfil the cooling demand for electronic devices installed with high-power integrated circuit packages (microchips). Various microchannel designs have been innovated to improve the heat transfer performance in an MCHS. Specifically, the utilisation of nanotechnology in the form of nanofluid in an MCHS attracted the attention of researchers because of considerable enhancement of thermal conductivity in nanofluid even at a low nanoparticle concentration. However, a high-pressure drop was the main limitation as it controls the MCHS performance resulted from heat transfer augmentation. Therefore, this study aimed to critically summarise the challenges and limitations of both single and hybrid passive methods of MCHS. Furthermore, the performance of nanofluid as a coolant in the MCHS as affected by the type and concentration of nanoparticle and the type of base fluid was reviewed systematically. The review indicated that the hybrid MCHS provides a better cooling performance than MCHS with the single passive method as the former results in a higher heat transfer rate with minimal pressure drop penalty. Besides that, further heat transfer performance can be enhanced by dispersing aluminium dioxide (Al2O3) nanoparticles with a concentration of less than 2.0% (v/v) in the water-based coolant.

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Section: Mchs With Hybrid Passive Methodsmentioning

confidence: 99%

A review of passive methods in microchannel heat sink application through advanced geometric structure and nanofluids: Current advancements and challenges

Japar

Sidik

Saidur

et al. 2020

Nanotechnology Reviews

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“…Xiong et al [69] numerically studied heat transfer in a microtube using roughness geometry with Gaussian distribution and observed negligible heat transfer enhancement from roughness. Lu et al [42] also used the Gaussian function to generate random 3D roughness in a microchannel at Re = 400. They observed that the pressure drop increases monotonically and the average Nusselt number remains unchanged with increasing relative roughness up to 1.2%, after which the Nusselt number increases with roughness.…”

Section: Nomenclaturementioning

confidence: 99%

CFD of roughness effects on laminar heat transfer applied to additive manufactured minichannels

2022

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Additive manufacturing has received significant interest in the fabrication of functional channels for heat transfer; however, the inherent rough surface finish of the additively manufactured channels can influence thermal performance. This study investigates the impact of roughness on the thermo-fluid characteristics of laminar forced convection in rough minichannels. A numerical model was developed to create 3D Gaussian roughness with specified root-mean-square height. The finite volume method was used to solve the conjugate heat transfer of developed laminar flow in square minichannels. For Reynolds numbers ranging from 200 to 1600, the simulation results indicated enhanced heat transfer and increased flow resistance as Reynolds number increases, compared to a smooth minichannel, where effects on heat transfer and flow friction were negligible. For channels with relative roughness (root-mean-square height to channel hydraulic diameter) of 0.0068, 0.0113, and 0.0167, increasing the Reynolds number led to increased friction factor by 1.56, 1.71, and 2.91%, while the Nusselt number was enhanced up to 0.03%, 32.74%, and 46.05%, respectively. Heat transfer reduced in roughness valleys due to the presence of local low-velocity fluid in these regions; however, recirculation regions can occur in deep valleys of high roughness, increasing heat transfer and flow friction. Heat transfer was enhanced over roughness peaks due to flow impingement on the windward face of roughness as well as intensified energy transfer to the channel wall from roughness. Moreover, surfaces with higher roughness have a greater number of high peaks providing a thermal-flow path of a larger area and a thermal conductivity greater than that of the fluid.

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“…They reported that roughness elements causing Nusselt number decline and pressure drop increase, as well as surface roughness reduces pin fin shape effect. Lu et al [25] studied numerically the effect of 2 % roughness in wall square, wave, and limped microchannel with Reynolds number of 500. They showed pressure drop and Nusselt number increase, which also affects the roughness depending on the microchannel's physical shape.…”

Section: A Surface Roughnessmentioning

confidence: 99%

A review of single-phase pressure drop characteristics microchannels with bends

Junianto

Hendrarsakti

2021

J. Mechatron. Electr. Power Veh. Technol.

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Microfluidic use in various innovative research, many fields aimed at developing an application device related to handling fluid flows in miniature scale systems. On the other hand, on the use of micro-devices for fluid flow the existence of bends cannot be avoided. This research aims to make a comprehensive study of fluid flow characteristics through a microchannel with several possible bends. This study was conducted by comparing Reynolds number versus pressure drop in a serpentine microchannel to gain bends loss coefficient. The result showed that the fluid flow with Re 100 did not affect the pressure drop, but on the Reynolds number above that, the pressure drop was increased along with the appears of vortices in the outer and inner walls around the channel bends which causes an increase in an additional pressure drop. The other finding shows that the reduction in diameter bend tube can increase the pressure drop.

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Effects of surface roughness in microchannel with passive heat transfer enhancement structures

Cited by 37 publications

References 27 publications

A review of passive methods in microchannel heat sink application through advanced geometric structure and nanofluids: Current advancements and challenges

A review of passive methods in microchannel heat sink application through advanced geometric structure and nanofluids: Current advancements and challenges

CFD of roughness effects on laminar heat transfer applied to additive manufactured minichannels

A review of single-phase pressure drop characteristics microchannels with bends

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