Prediction models of void fraction and pressure drop for gas-liquid slug flow in microchannels

Kurimoto, Ryo; Nakazawa, Kento; Minagawa, Hisato; Yasuda, T.

doi:10.1016/j.expthermflusci.2017.05.014

Cited by 36 publications

(19 citation statements)

References 23 publications

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“…The bubble volume was calculated from the bubble images recorded by the high‐speed camera using image processing 18,35 . A typical calculation process of the bubble volume is demonstrated in Figure 4.…”

Section: Experimental Partmentioning

confidence: 99%

High‐frequency formation of bubble with short length in a capillary embedded step T‐junction microdevice

et al. 2021

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The performances of slug flow gas–liquid reactors are mostly determined by slug length, especially for the high gas–liquid flow rate ratio condition. This work is the first time to report the short bubble generated with high frequency in a capillary embedded step T‐junction microdevice. The aspect ratio of bubble could be around 0.5 with a frequency higher than 750 s−1 when the gas–liquid flow rate ratio is even higher than 5. The specific surface area of the generated gas–liquid microdispersion system is larger than 10,400 m2/m3. The short bubble formation process includes two periods, and its formation mechanism is mainly because of the relatively higher pressure drop in the step T‐junction, which provides a much higher breakup force for the squeezing flow. Finally, two models are developed to predict the bubble frequency and volume. This work provides a highly promising dispersion technology for the gas–liquid process intensification in microreactors.

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Section: Experimental Partmentioning

confidence: 99%

High‐frequency formation of bubble with short length in a capillary embedded step T‐junction microdevice

et al. 2021

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“…To understand the effect of different liquids, CFD simulations have also been performed for three different liquids, water–glycerol (52% by wt) mixture; water–glycerol mixture (64% by wt); and ethylene glycol, at a mixture or two‐phase velocity of 0.3 ms −1 and void fraction of 0.3. These fluids have been considered by Kurimoto et al in their experiments for gas–liquid slug flow and cover a range of liquid viscosities (given in Table ). With an increase in liquid viscosity, the capillary number increases from 0.0037 to 0.098, whereas Reynolds number decreases from 336 to 21.…”

Section: Resultsmentioning

confidence: 58%

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

Kumari

Kumar

Gupta

2018

Asia-Pacific J Chem Eng

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The membrane processes generally suffer from the fouling caused by the deposits at the membrane surface and membrane pores. In recent years, gas-liquid flow has been shown to be an effective method of membrane fouling prevention. Among the different flow regimes that occur during gas-liquid flow through membrane capillaries, slug flow has been observed to be the most effective for enhancement of permeate flux. The shearing caused by the fluid on the membrane wall is the primary factor causing fouling removal. Previous studies in the slug flow regime suggest that the major contribution to the wall shear stress comes from the bubble front and rear regions and the contribution from the constant film thickness region in the middle is negligible. Therefore, the average wall shear stress in the slug flow regime is dependent on the bubble length. In this work, two-phase gas-liquid flow in a capillary has been modeled computationally to understand the effect of bubble length on the wall shear stress. Further, the effect of liquid viscosity on the wall shear stress has also been studied for capillary numbers ranging from 0.0037 to 0.098. The volume-of-fluid method has been employed to capture the gas-liquid interface between the two phases. The results have been compared with a simple phenomenological model for wall shear stress available in literature and found to be in good agreement for long Taylor bubbles.

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“…P is the initial pressure. The Semi-implicit method for pressure linked equations consistent (SIMPLEC) algorithm, which is based on continuity equation of Equation (12) and Equation ( 13) [21] [22], was employed for the calculation. And the solving process of velocity and pressure in the Venturi tube was illustrated in Figure 4.…”

Section: Methods and Simulationmentioning

confidence: 99%

Design Optimization Analysis of Venturi Tube for Medium Conveying in Strengthen Grinding Process

Xiao¹,

Liang²,

Liu³

et al. 2021

ENG

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Venturi tubes are widely used in manufacture and chemical industry and attract broad attention. To improve the transmission efficiency, the optimization of Venturi tube has been carried out, the transport substances involved in either liquid, solid, gas or two of them. The Venturi tubes that used for conveying of three-phase flow, which is consisted of solid, liquid and gas, are poorly investigated. In this paper, a Venturi tube employed in one surface treatment equipment was proposed. The velocity and pressure distribution in the flow field of Venturi tube with different key geometric parameters including diameter ratio, convergence angle and diffuser angle have been studied. One optimal solution has been selected. The negative pressure of suction port can reach a value as high as −1550 Pa to −1600 Pa. Such negative pressure offers the opportunities for transporting mixed abrasive.

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Prediction models of void fraction and pressure drop for gas-liquid slug flow in microchannels

Cited by 36 publications

References 23 publications

High‐frequency formation of bubble with short length in a capillary embedded step T‐junction microdevice

High‐frequency formation of bubble with short length in a capillary embedded step T‐junction microdevice

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

Design Optimization Analysis of Venturi Tube for Medium Conveying in Strengthen Grinding Process

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