Experimental Techniques for Bubble Dynamics Analysis in Microchannels: A Review

Mohammadi, Mahshid; Sharp, Kendra V.

doi:10.1115/1.4023450

Cited by 30 publications

(12 citation statements)

References 118 publications

(165 reference statements)

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“…The measured Taylor flow features dimensionless numbers, which are comparable to those of our study (Ca c = 0.003, Re c = 0.001, A r = 2.44, MD * = 0.084). Mohammadi and Sharp (2013) summarized the experimental methods to access the velocity distribution of Taylor flows. Meyer et al (2014) investigated vertically rising Taylor bubbles in a rectangular mini channel.…”

Section: Introductionmentioning

confidence: 99%

µPIV measurement of the 3D velocity distribution of Taylor droplets moving in a square horizontal channel

et al. 2020

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This paper presents a µPIV measurement of the 3D2C velocity distribution of Taylor droplets moving in a square horizontal microchannel at Ca c = 0.005 and Re c = 0.051. We reconstruct the third velocity component and present an accuracy assessment of the reconstruction based on a volume flow balance of the 3D3C velocity field. The velocity field allows the investigation of the 3D flow features such as stagnation regions and the shear rate distribution. The maximum shear rate is located at the entrances and exits of the wall films and at the corner flow (gutter) bypassing the Taylor droplet. The regions of high strain correspond to the cap positions of the Taylor droplets. An experimental data set allows visualization of the streamlines of the velocity distribution on the interface of a Taylor droplet and to directly relate it to the main and secondary vortices of the droplet phase velocity field. The measurement data are provided as a digital resource for the validation of numerical simulation or further assessment.

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Section: Introductionmentioning

confidence: 99%

µPIV measurement of the 3D velocity distribution of Taylor droplets moving in a square horizontal channel

et al. 2020

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“…High-speed photography and particle image velocimetry (PIV) are powerful tools in microfluidics [24,25]. Prior work on bubble-driven pumps was mostly focused on the bubble evolution as the vapor-fluid interface provides good optical contrast [16,26,27,28].…”

Section: Methodsmentioning

confidence: 99%

Single-pulse dynamics and flow rates of inertial micropumps

Govyadinov¹,

Kornilovitch²,

Markel³

et al. 2016

Microfluid Nanofluid

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Bubble-driven inertial pumps are a novel method of moving liquids through microchannels. We combine high-speed imaging, computational fluid dynamics (CFD) simulations and an effective one-dimensional model to study the fundamentals of inertial pumping. For the first time, single-pulse transient flow through Ushaped microchannels is imaged over the entire pump cycle with 4-µs temporal resolution. Observations confirm the fundamental N-shape flow profile predicted earlier by theory and simulations. Experimental flow rates are used to calibrate the CFD and one-dimensional models to extract an effective bubble strength. Then the frequency dependence of inertial pumping is studied both experimentally and numerically. The pump efficiency is found to gradually decrease once the successive pulses start to overlap in time.

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“…The role of bubble dynamics (bubble growth, bubble coalescence, and bubble collapse) in the onset of subcooled boiling instability is still unclear because of its very complex nature . The visualization techniques are very common for studying bubble dynamics in boiling channels and include high-speed photography, confocal scanning laser microscopy, and particle imaging velocimetry (PIV). − The most advanced visualization techniques such as PIV and particle tracking velocimetry (PTV) can also reveal deep insights of boiling flow structure and Reynolds stresses. The PIV is the most useful technique for measuring the velocity field of liquid flow in boiling channels …”

Section: Introductionmentioning

confidence: 99%

Onset of Flow Oscillation in a Natural Circulation Boiling Loop—Role of Bubble Dynamics

Bhati

Paruya

et al. 2021

Ind. Eng. Chem. Res.

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In the present work, we investigate bubble dynamics (bubble growth and collapse) and onset of flow oscillation in a natural circulation boiling loop (NCBL) using a high-speed camera (500 fps) and numerical simulation. The steady-state analysis of the loop flow rate yields the onset of flow oscillations and a marginal stability boundary, which are reasonably close to the experimental results. The simulation based on four-equation drift flux model predicts the amplitude and frequency of experimental flow oscillations. We observe that the growth and collapse of a vapor bubble with a critical diameter of 3.42 mm triggers the flow oscillation in the NCBL. The bubble diameter and shape play a major role in initiating the flow oscillation followed by spiral motion, path oscillation, and shape transition of the non-spherical bubbles. The numerical simulation satisfactorily predicts the flow oscillations.

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Experimental Techniques for Bubble Dynamics Analysis in Microchannels: A Review

Cited by 30 publications

References 118 publications

µPIV measurement of the 3D velocity distribution of Taylor droplets moving in a square horizontal channel

µPIV measurement of the 3D velocity distribution of Taylor droplets moving in a square horizontal channel

Single-pulse dynamics and flow rates of inertial micropumps

Onset of Flow Oscillation in a Natural Circulation Boiling Loop—Role of Bubble Dynamics

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