Thermal-hydraulic performance of a tapered microchannel

Cheng, Kai; Chong, Yi Sheng; Ooi, Kim Tiow

doi:10.1016/j.icheatmasstransfer.2018.03.008

Cited by 17 publications

(5 citation statements)

References 38 publications

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“…The methodology of implementing the microchannels is similar to the one adopted by [7][8][9][10][11][12]. A solid cylindrical insert with an external diameter of 19.4 mm is superimposed concentrically within a hollow cylindrical pipe with an internal diameter of 20 mm, yielding an annular gap of 300 µm as shown in Fig.…”

Section: Plain Microchannelmentioning

confidence: 99%

Investigation of Variable Cross-Sectional Flow Area for an Enhanced Thermo-Hydraulic Performance in Microchannels

Chua¹,

Cheng²,

Ooi³

2018

World Congress on Mechanical, Chemical, and Material Engineering

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The effect of variable cross-sectional flow area owing to the change in protrusion height along the flow direction, on the thermo-hydraulic performance was studied experimentally. A steady-state study that utilised single-phase water as the working fluid was conducted for Reynolds number range between 1100 and 4400, with a constant heat input of 1000 W along the microchannel length of 30 mm. Two microchannel configurations, namely (a) contracted cross-sectional flow area and (b) expanded cross-sectional flow area, were investigated together with a plain microchannel to evaluate the thermo-hydraulic performance. The average hydraulic diameters of the annular microchannels are kept constant at 600 µm for both configurations. The microchannel with an expanded cross-sectional flow area yielded the highest Nusselt number of 49.6 at Reynolds number of 4377. The same microchannel achieved the highest thermo-hydraulic performance index of 1.59 at Reynolds number of 1974, using the plain microchannel as the reference.

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Section: Plain Microchannelmentioning

confidence: 99%

Investigation of Variable Cross-Sectional Flow Area for an Enhanced Thermo-Hydraulic Performance in Microchannels

Chua¹,

Cheng²,

Ooi³

2018

World Congress on Mechanical, Chemical, and Material Engineering

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“…In an investigative study, 2 the effects of the diameter of microchannel on the pressure drop were studied; the experiments show that the microchannels with smaller diameters agree with the literature, whereas the ones with the larger diameter have some interference. Microchannels can be straight, 3 and they can be tapered as described by Chen et al 4 The recent techniques for fabricating microchannels are micro-milling, 5 hot embossing, 6 die casting, photolithography and injection moulding. The techniques such as photolithography, chemical etching and laser micromachining, which are prominently used in the fabrication of biosensors, have been reviewed by Bhatt et al 7 Since biocompatibility and transparency are crucial in developing these devices, polymers are used.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Hybrid machining of P20 die steel masters for the development of polymer-based microfluidic devices to study the effect of surface roughness on bacterial activity

Pandit

Samuel

2023

Journal of Micromanufacturing

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Compared to the traditional machining and finishing process, a hybrid technique consisting of mechanical micro-milling and electropolishing is advantageous in maintaining dimensional accuracy and fine surface quality without compromising the form. This is a cost-effective, less tedious technique that can fabricate high-quality masters for microfluidic devices. P20-die steel masters are fabricated to evaluate the method with this technique. The dimensional accuracy and surface quality of the masters are studied. It is found that the peak-to-valley surface roughness (Rt) of the masters is reduced by 50%. These die steel masters are then used to make polydimethylsiloxane (PDMS)-based microfluidic devices that could be used for particle separation. As biofouling and bacterial growth are undesirable in most of the microfluidic devices, the fabricated PDMS devices are tested for bacterial growth and adhesion. The growth of DH5α Escherichia coli bacteria in the devices fabricated using the electropolished masters is evaluated. Bacterial growth and adhesion are monitored for 0, 4 and 12 h, and it is found that the growth and adhesion in these devices are reduced by 15–20% and 40–50%, respectively, compared to the devices produced using non-electropolished masters. Enumeration of the bacterial cells in the samples flown is carried out by evaluating the optical density of the sample fluids by UV-visible spectroscopy and quantifying the bacterial cells using the McFarland 0.5 standard.

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“…Interruption and mixing of main flow using microstructures, and change in geometrical configurations have also been used by many researchers to augment turbulent heat transfer. Cheng et al [21] used four different tapered microchannels for Re ranging from 1300 -3400. Their results showed that an early turbulence could be achieved at low values of Re leading to a good heat transfer.…”

Section: Introductionmentioning

confidence: 99%

A study of turbulent heat transfer in convergent-divergent shaped microchannel with ribs and cavities using CFD

Srivastava¹,

Dewan²

2020

JMES

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This paper presents the effects of microchannel shape with ribs and cavities on turbulent heat transfer. Three-dimensional conjugate heat transfer using the SST k-ω turbulence model has been investigated for four different microchannels, namely, rectangular, rectangular with ribs and cavities, convergent-divergent (CD) and convergent-divergent with Ribs and Cavities (CD-RC). The flow field, pressure and temperature distributions and friction factor are analyzed, and thermal resistance and average Nusselt number are compared. The thermal performance of the CD-RC microchannel is found to be better than that of other microchannels considered in terms of an average Nusselt number increased from 16% to 40%. Heat transfer increases due to a strong fluid mixing and periodic interruption of boundary-layer. It is observed that with an increase in Reynolds number (Re), the thermal resitance drops rapidly. The thermal resistance of the CD-RC microchannel is decreased by 30% than that of the rectangular microchannel for Re ranging from 2500 to 7000. However, such design of microchannel loses its heat transfer effectiveness due to a high pumping power at high values of Re.

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Thermal-hydraulic performance of a tapered microchannel

Cited by 17 publications

References 38 publications

Investigation of Variable Cross-Sectional Flow Area for an Enhanced Thermo-Hydraulic Performance in Microchannels

Investigation of Variable Cross-Sectional Flow Area for an Enhanced Thermo-Hydraulic Performance in Microchannels

Hybrid machining of P20 die steel masters for the development of polymer-based microfluidic devices to study the effect of surface roughness on bacterial activity

A study of turbulent heat transfer in convergent-divergent shaped microchannel with ribs and cavities using CFD

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