Flow Configurations in a Y Splitting-Junction Microchannel

Sinibaldi, Giorgia; Romano, G. P.

doi:10.3390/fluids2020018

Cited by 4 publications

(1 citation statement)

References 9 publications

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“…The velocity field can be obtained using micro-particle image velocimetry (PIV), a non-invasive technique that allows to measure the velocity on planar sections (Steijn et al. 2007; Sinibaldi and Romano 2017). The accuracy is limited by the thickness of slab over which the field is implicitly averaged.…”

Section: Introductionmentioning

confidence: 99%

A T-junction device allowing for two simultaneous orthogonal views: application to bubble formation and break-up

Caprini

Sinibaldi

Marino

et al. 2018

Microfluid Nanofluid

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A novel design for the classical microfluidic device known as T-junction is proposed with the purpose of obtaining a simultaneous measurement of the in-plane velocity components in two orthogonal planes. A crucial feature of the proposed configuration is that all three velocity components are available along the intersection of the two planes. A dedicated optical set-up is developed to convey the two simultaneous views from the orthogonal planes into the sensor of a single camera, where a compound image is formed showing on either half one of the two views. A commercial micro-particle image velocimetry system is used to measure the velocity in the two planes. Feeding the T-junction with a liquid continuous phase and a dispersed gas phase, the velocity is measured by phase averaging along the bubble formation and break-up process showing the potentialities of the new design. The accuracy analysis shows that the error is dominated by a systematic component due to the thickness of the measurement slice. The error can be reduced by applying confocal microscopy to the present system with no further modifications so as to reduce the thickness of the measurement slab thereby reducing the error. Moreover, by sweeping the planes across the region of interest, a full three-dimensional reconstruction of the velocity field can be readily obtained. Finally, the simultaneous views offer the possibility to extract the principal curvatures of the bubble meniscus thereby providing access to the Laplace pressure.

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Section: Introductionmentioning

confidence: 99%

A T-junction device allowing for two simultaneous orthogonal views: application to bubble formation and break-up

Caprini

Sinibaldi

Marino

et al. 2018

Microfluid Nanofluid

Self Cite

View full text Add to dashboard Cite

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A parametric study of laminar convective heat transfer in fractal minichannels with hexagonal fins

et al. 2019

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The excess heat generated by the modern electronic components and devices leads to a sustained growth in demand for thermal management technologies. Inspired by the features of fractal structures in terms of the periodical interruption of boundary layer and the strong flow mixing, a parametric study is carried out to study the flow and heat transfer performance in the fractal minichannels configured with hexagonal fins. A dimensionless performance factor involving average Nusselt number and average friction factor is defined to evaluate the overall performance with considering heat transfer enhancement and additional friction loss. The parametric effects of branching angle θ (60°-120°) and relative hexagonal side length α (1.00-2.00) on laminar hydrodynamics and thermal characteristics in the proposed minichannels are numerically investigated for Reynolds number ranged from 50 to 550. The results emphasize a lower temperature and more uniform temperature distribution on the bottom surface and an advantage of overall performance for the fractal minichannel with hexagonal fins over the conventional straight minichannel. It is noted from the results that the variation of branching angle possesses little effect on the maximum temperature and temperature uniformity of the bottom surface. On the basis of the evolution of the performance factors, the best performance is obtained by the branching angle of 60°and the relative hexagonal side length of 1.50 among the tested configurations, and the maximum temperature and temperature uniformity of the bottom surface are reduced by 16.4 K and 84%, respectively, when comparing with the straight channel as the reference object. This study verified the theoretical conjecture that the application of hexagonal fins in minichannel plays an important role in effectively improving heat transfer in the case of controllable pressure loss.

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