Effect of gas–liquid ratio on the wall shear stress in slug flow in capillary membranes

Kumari, Sadhana; Kumar, Nilay; Gupta, Raghvendra

doi:10.1002/apj.2258

Cited by 5 publications

(3 citation statements)

References 33 publications

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“…The velocity of the spherical bubble, U 1 , is more than that of the Taylor bubble, U 2 , and it approaches towards the Taylor bubble with a velocity U 1 − U 2 . In our previous work, [ 5,6 ] the moving domain method was used to simulate periodic Taylor flow in a unit cell consisting of a bubble and two adjacent halves of liquid slug in the bubble frame of reference. The bubble is placed in the middle of the computational domain and its velocity is calculated dynamically using Equation ):

U_{Domain} = \frac{\int_{x}^{x + L} \int_{0}^{R} α_{G} v_{x} ((), 2 italicπr) italicdrd x^{'}}{\int_{x}^{x + L} \int_{0}^{R} α_{G} ((), 2 italicπr) italicdrd x^{'}}

…”

Section: Cfd Methodologymentioning

confidence: 99%

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Hydrodynamics of bubble coalescence in microchannels

2020

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Gas‐liquid flow in microchannels is relevant to a number of microfluidic devices without moving parts for application in chemical micro‐processing, inkjet printing, and electronics cooling. Over a large range of gas and liquid flow rates, gas bubbles have the same size as that of the channel. Such bubbles are nearly spherical in shape until their radius is less than that of the channel. The bubbles with a larger volume expand along the axis taking a capsular or bullet shape and are commonly known as Taylor bubbles. For air‐water flow, the spherical bubble is observed to move with a velocity higher than that of the Taylor bubble. In this work, the flow of a Taylor bubble followed by a spherical one, initially separated by several channel diameters, has been studied numerically using the volume of fluid (VOF) method. The hydrodynamics during the bubble approach as well as the evolution of the doublet, that is, the merged bubble, has been investigated. To track the velocity of each bubble with time during the bubble approach stage, a novel methodology has been developed using k‐means clustering algorithm. The evolution of the interface of the doublet has been monitored. The neck radius of the doublet grows as τ0.5, τ being the time since the contact between the bubble interfaces, when the interface is away from the wall. In the near wall region, the radius grows more slowly and is proportional to τ0.1.

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U_{Domain} = \frac{\int_{x}^{x + L} \int_{0}^{R} α_{G} v_{x} ((), 2 italicπr) italicdrd x^{'}}{\int_{x}^{x + L} \int_{0}^{R} α_{G} ((), 2 italicπr) italicdrd x^{'}}

…”

Section: Cfd Methodologymentioning

confidence: 99%

“…It was seen that for large values of Reynolds number, a bubble of smaller volume moves at a higher velocity for a given value of capillary number. In recent studies, Kumari et al [ 5,6 ] have shown that for air‐water flow in small diameter channels, the velocity of spherical bubble is higher than that of a long Taylor bubble.…”

Section: Introductionmentioning

confidence: 99%

Hydrodynamics of bubble coalescence in microchannels

2020

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“…The interfacial friction factor between the gas core and liquid film can be calculated as follows:

f_{i} = f_{g} ((), 1 + 14.3 H_{lf}^{0.5} ((), \frac{v_{italicsg}}{v_{sg . t}} - 1)),

where

v_{italicsg, t} = 5 {(\frac{ρ_{italicgo}}{ρ_{g}})}^{0.5}

and ρ go is the gas density at atmospheric pressure.…”

Section: Theoretical Modellingmentioning

confidence: 99%

Modelling and analysis of impact forces acting on elbow in gas–liquid slug flow

Xiao

Jing

Han³

et al. 2018

Asia-Pacific J Chem Eng

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The impact forces caused by gas-liquid slug flow can lead to the vibration of process system or fatigue failure of pipe fittings. In this study, a piston-flowmodel coupling with slug model is developed to calculate the impact forces, which can contribute to the structure design and flow assurance. An experiment installation is installed to study the characteristics of slug flow and validate the reliability of the model. The accuracy of this model is above 90% for the superficial velocity of gas below 2 m/s, whereas the average deviation is 29.2% for the cases of superficial velocity of gas above 2 m/s. The modified model addressing the liquid holdup agrees well with the experimental data, of which the average deviation is 6.25%.

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