Fringe probing of liquid film thickness of a plug bubble in a micropipe

Wang, Xishi; Qiu, Huihe

doi:10.1088/0957-0233/16/2/037

Cited by 14 publications

(8 citation statements)

References 12 publications

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“…Based on the method proposed by Wang and Qiu [1], the film thickness measurement method is further extended. Figure 1 shows the schematic of a moving bubble in a capillary pipe where the advancing and receding contact angles are different at the front and the end of the bubble.…”

Section: Methodsmentioning

confidence: 99%

“…The motion of the bubble can make the spatial frequency of the fringes change. According to Wang and Qiu (2005) the measured spatial frequency is a function of the film thickness at that location being measured [1]. Figure 2, the relation between 2D film thickness h(z) and the spatial frequency of the scattering fringes can be described by equation 1:…”

Section: Methodsmentioning

confidence: 99%

“…where, β is the orientation angle of the receiving optics (CCD camera) and g n , l n is the refractive index of the glass and the liquid respectively. 1, R and c is known; 0 f (z) and f (z) can be calculated by the fringes received from high speed CCD camera; the incident angle θ (z) can be calculated by the iterative method (Wang and Qiu (2005)). The film thickness can then be obtained through the equation (1).…”

Section: Methodsmentioning

confidence: 99%

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2D fringe probing of liquid film dynamics of a plug bubble in a micropipe

Qiu

2008

Meas. Sci. Technol.

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Research on bubble dynamics and heat transfer in micropipe two-phase flows is an important area in micro electronic cooling, microfluidics and non-invasive laser/ultrasound microsurgery. For example, a pulsating heat pipe (PHP) is a very effective heat transfer device which made of a relatively long and thin sealed pipe containing both phases of the working fluid. The inner diameter of the pipe must be sufficiently small so that vapor bubbles can grow to vapor plugs in the tube. The optical diagnostic technique developed by Wang and Qiu (2005) has been further extended to probe 2D interfacial film thickness in micro capillary two-phase flows. Similar to single point measurements, the spatial frequencies from the multi-scattering measured by CCD camera are used to determine the film thickness but whole fringe image is divided into N columns for determining the special frequencies. The spatial frequency of each image column can be used to calculate the interfacial film thickness of the segment of the plug bubble. By integrating all the measured film thickness along the bubble, the interfacial film surround the whole bubble can be determined. The very fine parallel fringes are projected onto the liquid/gas-bubble interface. The scattered fringe pattern can be imaged at a proper orientation angle where the spatial frequency of the fringe pattern can be measured. To determine the spatial frequency variations during the plug/slug pulsating, a highly accurate signal processing technique for continuously evaluation of signal phases utilizing a modified fast Fourier transform algorithm was used. Through geometrical optics approach, the curvature of the cross-section of a plug can be derived from the spatial frequency of the scattering pattern on the screen. Capillary tubes, with inner diameters of 1.0mm and 0.3mm, and a length of 65mm, are used. A gas plug bubble, 5mm~20mm long, is introduced and moves through the testing part of tube, which is filled with water as the working fluid. The interference fringes produced by two incident laser sheets are scattered from the interface between gas and water, and captured by high speed camera at the speed of up to 2000 frames per second. The experimental results show that the improved method can obtain the liquid film thickness profile at the different time and can be used to analyze the status of plug bubble movement in a micropipe.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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2D fringe probing of liquid film dynamics of a plug bubble in a micropipe

Qiu

2008

Meas. Sci. Technol.

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“…In particular, gas–aqueous liquid two–phase flow plays an important role in a range of applications including information processing, micro heat exchanger, and lab-on-a-chip systems where mixing two fluids to prepare for further treatment is frequently desirable to obtain certain chemical reactions or to perform chemical analysis 6 7 8 9 . Given that the characteristics (length, volume, number, flow rate, and shape) of a segmented gas slug significantly affect to the enhancement of mixing, mass transfer, and heat transfer rate of the microfluidic system, the characterization of a gas slug in a two-phase flow has become significant to improve the performance of devices 3 10 11 12 13 14 15 16 . Moreover, it is also important in the biological and industrial systems to understand the reaction kinetics 17 .…”

mentioning

confidence: 99%

“…To characterize configuration of gas-aqueous liquid two-phase flow (especially a gas slug) several techniques have been previously developed 13 17 18 19 20 21 . The available characterization strategies are mostly based on measuring the distorted laser light path attributed to the change in refractive index as a result of the presence of gas slugs 17 18 .…”

mentioning

confidence: 99%

A Simple Approach to Characterize Gas-Aqueous Liquid Two-phase Flow Configuration Based on Discrete Solid-Liquid Contact Electrification

Choi

Lee

Kim

2015

Sci Rep

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In this study, we first suggest a simple approach to characterize configuration of gas-aqueous liquid two–phase flow based on discrete solid-liquid contact electrification, which is a newly defined concept as a sequential process of solid-liquid contact and successive detachment of the contact liquid from the solid surface. This approach exhibits several advantages such as simple operation, precise measurement, and cost-effectiveness. By using electric potential that is spontaneously generated by discrete solid–liquid contact electrification, the configurations of the gas-aqueous liquid two-phase flow such as size of a gas slug and flow rate are precisely characterized. According to the experimental and numerical analyses on parameters that affect electric potential, gas slugs have been verified to behave similarly to point electric charges when the measuring point of the electric potential is far enough from the gas slug. In addition, the configuration of the gas-aqueous liquid two-phase microfluidic system with multiple gas slugs is also characterized by using the presented approach. For a proof-of-concept demonstration of using the proposed approach in a self-triggered sensor, a gas slug detector with a counter system is developed to show its practicality and applicability.

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Measurement of thin liquid film thickness in pipes based on optical interferometry

Xue

2022

Optoelectron. Lett.

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Fringe probing of liquid film thickness of a plug bubble in a micropipe

Cited by 14 publications

References 12 publications

2D fringe probing of liquid film dynamics of a plug bubble in a micropipe

2D fringe probing of liquid film dynamics of a plug bubble in a micropipe

A Simple Approach to Characterize Gas-Aqueous Liquid Two-phase Flow Configuration Based on Discrete Solid-Liquid Contact Electrification

Measurement of thin liquid film thickness in pipes based on optical interferometry

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