The effect of bubble deceleration on the liquid film thickness in microtubes

Youn, Young Jik; Muramatsu, K.; Han, Youngbae; Shikazono, Naoki

doi:10.1016/j.ijheatfluidflow.2016.01.002

Cited by 17 publications

(6 citation statements)

References 18 publications

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“…In doing so, the CFD technique with the approach of volume of fluid (VoF) has been used, in combination with a moving mesh. The numerical results of the liquid film thickness left behind receding meniscus at different constant velocities has been validated with experimental data reported in literature [9] to tune the hydrodynamic CFD model. Instead of using high grid resolution along the length of the capillary, the moving overset grid approach is used to follow the meniscus region in order to reduce the number of cells and the computational time.…”

Section: Introductionmentioning

confidence: 55%

“…The accuracy of the numerical results is validated by comparison with experimental data for the liquid film thickness, reported at steady condition by Youn et al [9]. To compare the numerical results with the experimental data, in addition to material properties and the tube geometry, the meniscus velocity should be the same for both cases.…”

Section: Validation Of Numerical Resultsmentioning

confidence: 86%

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CFD Modelling Of Film Deposition from a Receding Meniscus in a Capillary Tube Using the Approach of Overset Grid Technique

Nikkhah¹,

Karami²,

Tessier-Poirier³

et al. 2022

International Conference on Fluid Flow, Heat and Mass Transfer

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Meniscus motion in a capillary tube is a very common type of flow in thermal management devices such oscillating and pulsating heat pipes. It is well known, that the thin film deposited on the wall, which is due to liquid shear force, plays a major role in heat and mass transfer of those devices. This study focuses on the hydrodynamics of this flow using a CFD axisymmetric model of a 1mm diameter capillary, with the approach of volume of fluid (VoF). The CFD-VOF approach is tuned to capture the liquid film deposition from a receding meniscus at different constant velocities. Due to high required grid resolution, the moving overset mesh technique is used. In doing so, a fine meshed domain consists of meniscus slides over the background domain with a coarse mesh. By using this technique, the number of cells and computational time reduced considerably in comparison with regular meshing approach. With water as a working fluid, the numerical results for the liquid film thickness, at different velocities, compare well with experimental data from the literature. The simulations also show that at higher capillary number, the axial location where the film thickness becomes constant moves away from the meniscus nose. The shear stress distribution indicates higher values near the meniscus compared to uniform film and liquid plug zones which is due to the interface curvature in this zone. Also, a recirculating flow was observed within the liquid film left behind the receding meniscus which could have favourable effects in terms of heat and mass transfer. The present work on hydrodynamics is the first step toward complete modelling of an oscillating meniscus with mass and heat transfer inside the capillaries.

show abstract

Section: Introductionmentioning

confidence: 55%

Section: Validation Of Numerical Resultsmentioning

confidence: 86%

CFD Modelling Of Film Deposition from a Receding Meniscus in a Capillary Tube Using the Approach of Overset Grid Technique

Nikkhah¹,

Karami²,

Tessier-Poirier³

et al. 2022

International Conference on Fluid Flow, Heat and Mass Transfer

View full text Add to dashboard Cite

show abstract

“…In doing so, the CFD technique with the approach of the volume of fluid (VoF) has been used, in combination with a moving mesh. The numerical results of the liquid film thickness left behind receding meniscus at different constant velocities have been validated with experimental data reported in the literature [9] to tune the hydrodynamic CFD model. Instead of using high grid resolution along the length of the capillary, the moving overset grid approach is used to follow the meniscus region to reduce the number of cells and the computational time.…”

Section: Introductionmentioning

confidence: 62%

“…The accuracy of the numerical results is validated by comparison with experimental data for the liquid film thickness, reported at steady conditions by Youn et al [9]. To compare the numerical results with the experimental data, in addition to material properties and the tube geometry, the meniscus velocity should be the same for both cases.…”

Section: Validation Of Numerical Resultsmentioning

confidence: 86%

Numerical Modelling Of Liquid Film Deposition from Moving Meniscus in a Capillary Tube

Nikkhah¹,

Karami²,

Tessier-Poirier³

et al. 2022

JFFHMT

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Meniscus motion in a capillary tube is a very common type of flow in thermal management devices such as oscillating and pulsating heat pipes. It is well known, that the thin film deposited on the wall, which is due to liquid shear force, plays a major role in the heat and mass transfer of those devices. This study focuses on the hydrodynamics of this flow using a CFD axisymmetric model of a 1mm diameter capillary, with the approach of the volume of fluid (VoF). The CFD-VOF approach is tuned to capture the liquid film deposition from a receding meniscus at different constant velocities. Due to the high required grid resolution, the moving overset mesh technique is used. In doing so, a fine-meshed domain consists of meniscus slides over the background domain with a coarse mesh. By using this technique, the number of cells and computational time are reduced considerably in comparison with the regular meshing approach. With water as a working fluid, the numerical results for the liquid film thickness, at different velocities, compare well with experimental data from the literature. The simulations also show that at a higher capillary number, the axial location where the film thickness becomes constant moves away from the meniscus nose. The shear stress distribution indicates higher values near the meniscus compared to uniform film and liquid plug zones which is due to the interface curvature in this zone. Also, a recirculating flow was observed within the liquid film left behind the receding meniscus which could have favorable effects in terms of heat and mass transfer. The present work on hydrodynamics is the first step toward complete modeling of an oscillating meniscus with mass and heat transfer inside the capillaries.

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“…The average thickness of the liquid film varies based on capillary number in each combination of working liquid and channel orientation. In addition, the dashed lines show the liquid film thickness based on the semi-empirical correlation under the steady condition (i.e., the liquid column moving at constant velocity) proposed by Han and Shikazono (2009a) and Youn et al (2016).…”

Section: の熱輸送機構，特に潜熱輸送機構の詳細な理解において，流路内で液柱往復振動に伴い生じる液膜挙動を明らかmentioning

confidence: 99%

Study on liquid film formed with liquid column oscillation in pulsating heat pipe (Measurement of liquid film thickness using forced oscillation system)

Matsuda

Arai

Ogura

et al. 2019

Transactions of the JSME (In Japanese)

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In order to gain a better understanding of the latent heat transfer mechanism in pulsating heat pipes (PHPs), this study experimentally investigated the thickness characteristics of a liquid film that forms during oscillations of the liquid column within PHPs. Accordingly, the liquid column was oscillated sinusoidally under different oscillating conditions to simulate the flow phenomena. A circular tube with an inner diameter of 2 mm was used as the test channel; ethanol and FC-40 were used as working liquids. The average thickness of the liquid film formed due to the liquid column oscillations on the channel wall was determined by comparing the oscillation amplitudes of the tip of the liquid column obtained with and without the liquid film. It was confirmed that the average thickness of the liquid film varied based on the average capillary number for each working liquid. The time-average velocity of the tip of the liquid column, which was derived based on the assumption that the tip of the liquid column oscillates sinusoidally, was used as the characteristic velocity to calculate the average capillary number. The experimental results were compared with various correlations proposed in previous studies. The results show that the acceleration of the oscillating liquid column affected the liquid film thickness for a high average capillary number. For this high average capillary number, the rate of increase in liquid film thickness with the average capillary number decreased, and the liquid film thicknesses during the liquid column oscillation approached those under the steady condition. Furthermore, the liquid film thicknesses for the vertical channel were compared with those for the horizontal channel, and it was made clear that the effect of gravity on liquid film thickness is significant. Thus, the thickness characteristics of a liquid film during the liquid column oscillation within PHPs were clarified.

show abstract

The effect of bubble deceleration on the liquid film thickness in microtubes

Cited by 17 publications

References 18 publications

CFD Modelling Of Film Deposition from a Receding Meniscus in a Capillary Tube Using the Approach of Overset Grid Technique

CFD Modelling Of Film Deposition from a Receding Meniscus in a Capillary Tube Using the Approach of Overset Grid Technique

Numerical Modelling Of Liquid Film Deposition from Moving Meniscus in a Capillary Tube

Study on liquid film formed with liquid column oscillation in pulsating heat pipe (Measurement of liquid film thickness using forced oscillation system)

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