Liquid and gas flows in microchannels of varying cross section: a comparative analysis of the flow dynamics and design perspectives

Hemadri, Vadıraj; Duryodhan, V. S.; Agrawal, Amit

doi:10.1007/s10404-018-2034-8

Cited by 8 publications

(7 citation statements)

References 24 publications

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“…Nusselt number decreases with increasing flow rate, but involvement of flow mixing mechanism such as flow recirculation may improve it. Earlier, investigations suggest flow reversal to exists in diverging channel, 27 but secondary flow development in only one case in this study suggests that formation of secondary flow depends on the aspect ratio at the inlet cross-sectional area of the diverging channel.…”

Section: Discussioncontrasting

confidence: 52%

“…Hemadri et al. 27 compared the streamwise variation of forces in converging and diverging channel for both liquid and gas flows, in which the 12° diverging channel is used. They attributed the cause of backflow in liquid flows in diverging channel to the vena contracta effect.…”

Section: Resultsmentioning

confidence: 99%

“…Following conclusions are drawn from the analysis: Nusselt number decreases with increasing flow rate, but involvement of flow mixing mechanism such as flow recirculation may improve it. Earlier, investigations suggest flow reversal to exists in diverging channel, 27 but secondary flow development in only one case in this study suggests that formation of secondary flow depends on the aspect ratio at the inlet cross-sectional area of the diverging channel. Temperature uniformity is obtained with increasing flow rates, at the cost of deteriorating Nusselt number, and it decreases with increase in channel depth. For uniform temperature distribution with high heat transfer capacity both channel depth and flow rates need to be worked out simultaneously. The Nusselt number is higher for the case with lower channel depths, at a trade-off of higher pressure drop, due to high surface to volume ratio of fluid element. At larger channel depth, involvement of other fluid mixing mechanism, can enhance the heat transfer capacity. On the onset of secondary flows and least pressure drop, overall efficiency of case with N= 70 and H c = 200 µm is highest at flow rate of 15 ml/min, while for rest of the cases N= 45 is superior at all flow rates and at all channel depths. …”

Section: Discussionmentioning

confidence: 97%

“…A comparative study for liquid and gas in channel with varying cross section is performed by Hemadri et al. 27 They observed that due to compressibility and rarefaction effects the gas flow characteristics differ from those of liquid flows. The equivalent hydraulic diameter in liquid flow depends only on length of channel, while Knudsen number comes into picture in case of gas flows.…”

Section: Introductionmentioning

confidence: 99%

“…For water flow in diverging channel, flow reversal is observed due to the negative pressure gradient at the inlet region, after which the forces balanced rapidly and no flow separation is obtained in the diverging channel, which causes a calm flow with very low kinetic energy. 27…”

Section: Introductionmentioning

confidence: 99%

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This paper numerically investigates heat transfer performance and characteristics in single-phase liquid cooling in microchannels with radial arrangement of fins having inherent symmetry to mitigate the problem of flow maldistribution. The effects of number of fins, channel depth and flow rate on Nusselt number and substrate temperature are obtained. The relative thermal performance and overall efficiency are compared with respect to two different base cases having minimum number of channels and minimum channel depth. For increasing values of flow rate and channel depth, contradicting effects in terms of temperature uniformity are obtained. By varying only number of channels, has no significance until it is coupled with channel depth, which suggests that aspect ratio of inlet cross-sectional area should be considered as a significant factor which is capable of generating secondary flows in single phase liquid flows. The overall efficiency of case with 70 number of channels, 200 µm depth and 15 ml/min is found to be highest.

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Section: Discussioncontrasting

confidence: 52%

Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Proceedings of the Institution of Mechanical Engineers, Part E:

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CFD simulation of combined electroosmotic-pressure driven micro-mixing in a microchannel equipped with triangular hurdle and zeta-potential heterogeneity

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Jamaati

Bahiraei

2019

Chemical Engineering Science

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Experimental investigation on steam flow loss characteristics in microchannels

Yin

Wang

et al. 2021

AIP Advances

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In this paper, experiments were performed to investigate the flow loss characteristics of steam through different microchannels. The microchannels were assembled from stainless steel machined flange assemblies and pipes. The inlet pressure was 20 kPa, and the outlet pressure was adjusted between 5 kPa and 16 kPa (absolute pressure). The steam flow rate in microchannels was obtained by condensing the steam through a condenser coil, and the effects of microchannels of different structures and dimensions on the friction factor were studied by experiment. Experimental results show that the gas flow is not choking, even if the pressure ratio between the inlet and the outlet is as high as 4. In addition, a new correlation between the volumetric flow rate and the pressure difference was derived, and the error between the prediction curve and experimental data is within 20%. Besides, the microchannels’ structure effects on flow loss were investigated. The single most striking observation to emerge from the data comparison was that the gas flow phenomena in grooved channels with different hydraulic diameters were contrary. For microchannels with a hydraulic diameter of 300 µm, higher steam outlet velocities are found when steam flows in specially constructed microchannels. However, the opposite phenomena were observed in microchannels with a hydraulic diameter of 500 µm.

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Liquid and gas flows in microchannels of varying cross section: a comparative analysis of the flow dynamics and design perspectives

Cited by 8 publications

References 24 publications

Performance evaluation of simple radial fin design for single phase liquid flow in microchannel heat sink

Performance evaluation of simple radial fin design for single phase liquid flow in microchannel heat sink

CFD simulation of combined electroosmotic-pressure driven micro-mixing in a microchannel equipped with triangular hurdle and zeta-potential heterogeneity

Experimental investigation on steam flow loss characteristics in microchannels

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