Influence of structured surface roughness peaks on flow and heat transfer performances of micro- and mini-channels

Ansari, Munib Qasim; Zhou, Guobing

doi:10.1016/j.icheatmasstransfer.2019.104428

Cited by 19 publications

(3 citation statements)

References 39 publications

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“…The research showed that changes in the viscous shear stress and the heat transfer coefficient follow the roughness structure, increasing over roughness peaks and decreasing in roughness valleys, as shown in Figure 11 and Figure 12 . In terms of roughness modeling, Ansari et al [ 83 ], Li et al [ 84 ], Gamrat et al [ 85 ], and Croce et al [ 86 , 87 ] proposed different methods, respectively. Majumdar et al [ 88 ] used fractal to characterize the multiscale self-affine topography by scale-independent parameters such as the fractal dimension.…”

Section: Flow and Heat Transfer Mechanism Of Single-phase Fluid Under...mentioning

confidence: 99%

A Review of the Complex Flow and Heat Transfer Characteristics in Microchannels

Zhang

Zou

2023

Micromachines

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Continuously improving heat transfer efficiency is one of the important goals in the field of energy. Compact heat exchangers characterized by microscale flow and heat transfer have successfully provided solutions for this purpose. However, as the characteristic scale of the channels decreases, the flow and heat transfer characteristics may differ from those at the conventional scale. When considering the influence of scale effects and changes in special fluid properties, the flow and heat transfer process becomes more complex. The conclusions of the relevant studies have not been unified, and there are even disagreements on some aspects. Therefore, further research is needed to obtain a sufficient understanding of flow structure and heat transfer mechanisms in microchannels. This article systematically reviews the research about microscale flow and heat transfer, focusing on the flow and heat transfer mechanisms in microchannels, which is elaborated in the following two perspectives: one is the microscale single-phase flow and heat transfer that only considers the influence of scale effects, the other is the special heat transfer phenomena brought about by the coupling of microscale flow with special fluids (fluid with phase change (pseudophase change)). The microscale flow and heat transfer mechanisms under the influence of multiple factors, including scale effects (such as rarefaction, surface roughness, axial heat conduction, and compressibility) and special fluids, are investigated, which can meet the specific needs for the design of various microscale heat exchangers.

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Section: Flow and Heat Transfer Mechanism Of Single-phase Fluid Under...mentioning

confidence: 99%

A Review of the Complex Flow and Heat Transfer Characteristics in Microchannels

Zhang

Zou

2023

Micromachines

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“…For an accurate prediction of fluid dynamics and heat transfer, the geometry of the actual roughness must be resolved in the computation [65], the most important step of which is to generate the roughness. Several studies have used simple abstraction using various regular geometry forms [46,49,[54][55][56][66][67][68]. However, using regular elements to represent roughness has several issues, the most important being the impact of the shape and arrangement of the roughness elements on the results [54,55,66].…”

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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“…Even though use of fan-shaped ribs does not result in any drag reduction, it can enhance thermal transport under certain geometrical conditions [85,108]. Heat transfer rate was also studied under aligned and offset roughness patterns within microchannels, and no augmentation was achieved in the latter [139,140]. The underlying physics of thermal transport enhancement can be attributed to the periodic hydrodynamic and thermal boundary layer redevelopment over the microstructures [141].…”

Section: Thermal Transport and Microtexturingmentioning

confidence: 99%

Hydrodynamic and thermal characteristics of flow in textured microchannel

Rabiei

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Reduced length-scales in microchannels are highly advantageous for efficient manipulation of the flow and mixing in biochemical devices, as well as enhancing heat transfer, making them an ideal candidate for microelectronics cooling applications. However, these benefits come at the expense of increased pumping power requirements, which can be reduced by using surface mixrotexturing. Textured surfaces have shown encouraging results in terms of drag reduction in external flows and at larger scales (turbulent regime). However, there have been some discrepancies in the literature regarding the possibility of drag/friction reduction in micro-scale internal flows (laminar regime), which is believed to be due to the absence of a proper definition for the reference baseline.

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Influence of structured surface roughness peaks on flow and heat transfer performances of micro- and mini-channels

Cited by 19 publications

References 39 publications

A Review of the Complex Flow and Heat Transfer Characteristics in Microchannels

A Review of the Complex Flow and Heat Transfer Characteristics in Microchannels

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

Hydrodynamic and thermal characteristics of flow in textured microchannel

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