Characteristics of slug flow with inertial effects in a rectangular microchannel

Yao, Chaoqun; Zhao, Yuchao; Ye, Chunbo; Dang, Minhui; Dong, Zhengya; Chen, Guangwen

doi:10.1016/j.ces.2013.03.046

Cited by 78 publications

(14 citation statements)

References 52 publications

(150 reference statements)

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“…Chaoqun et al (5) 의 경우는 속도가 높게 예측이 되었고, Yue et al (9) 의 경우는 수력직경이 600 ㎛인 경우에 대해 식(11) 의   의 값을 0.8로 두고 적용하여 비교적 잘 예측이 됨을 확인하였다. Chaoqun et al (5) 의 경우 수력직경이 약 400 ㎛로 본 연구에서 사용한 유로보다 작으며, 유 로의 직경이 감소함(Yue et al (9) 과 Fukano and Kariyasaki (12) )에 따라   의 값이 증가하는 경향에 의해 예측 의 오차가 발생한 것으로 사료된다. …”

Section: 기포 속도 모델 적용 결과unclassified

Study on the Characteristics of Bubble and Liquid Slugs for Gas-Liquid Taylor Flow in a Rectangular Micro-channel

Lee¹,

Lee²

2015

Korean Journal of Air-Conditioning and Refrigeration Engineerin

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The characteristics of gas-liquid Taylor (Slug) flow in a square micro-channel of 600×600 ㎛ were investigated experimentally in this paper. The test fluids were nitrogen and water. The liquid and gas superficial velocities were 0.01 ～3 m/s and 0.1～3 m/s, respectively. Bubble and liquid slug length, bubble velocity, and frequency were measured by analyzing optical images using a high speed camera. Bubble length decreased with higher liquid flow rate, which increased dramatically with higher gas flow rate. However, slug length did not vary with changes in inlet liquid conditions. Additionally, bubble velocities and frequencies increased with higher liquid and gas flow rates. It was found that measured bubble lengths were in good agreement with the empirical models in the existing literature, but slug lengths were not.Key words Micro-channel(미세관), Two-phase flow(2상 유동), Taylor flow(Taylor 유동), Bubble(기포), Slug(슬러그) †Corresponding author, E-mail: jklee99@kyungnam.ac.kr (Fig. 1).기존의 Taylor 유동과 관련한 많은 연구들이 Taylor 기포의 길이를 측정하고 여러 가지 입구조건에 대해 길이를 예측하는 데에 집중되어 있는데, 유로에서의 압 력강하와 물질전달 등을 결정하는데 중요한 인자가 되 기 때문이다. 기포 길이에 대한 기존 연구에 대해, 기 포가 유로를 대부분 채워서 흐르는 Taylor flow가 주로 발생하는 Ca 수(  )가 작은 경우에 대해(sq-

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Section: 기포 속도 모델 적용 결과unclassified

Study on the Characteristics of Bubble and Liquid Slugs for Gas-Liquid Taylor Flow in a Rectangular Micro-channel

Lee¹,

Lee²

2015

Korean Journal of Air-Conditioning and Refrigeration Engineerin

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“…The experimental data are predicted with a mean absolute error (MAE) of 21.6%, and 85.6% of all predictions fall within an error band of ±30%. The model performance is also benchmarked against the experimental data of Chaoqun et al [13] in Figure 6b, and successfully predicts film thickness with an MAE of 21.8%; 77.8% of all predictions fall within an error band of ±30%. For this comparison, film thicknesses taken at Ca values in excess of 0.01 in the original study have been omitted; beyond this threshold, the higher aspect ratio of the channel showed strong inertial effects leading to liquid pooling in the narrow ends of the channel [13].…”

Section: Interface Characterization and Modelingmentioning

confidence: 99%

“…The model performance is also benchmarked against the experimental data of Chaoqun et al [13] in Figure 6b, and successfully predicts film thickness with an MAE of 21.8%; 77.8% of all predictions fall within an error band of ±30%. For this comparison, film thicknesses taken at Ca values in excess of 0.01 in the original study have been omitted; beyond this threshold, the higher aspect ratio of the channel showed strong inertial effects leading to liquid pooling in the narrow ends of the channel [13]. The film thickness measurements from the literature were obtained using an approach that relied on significant simplifying assumptions regarding bubble interface geometry, which may be responsible for the discrepancies in the comparison of the present model and the experimental data of Chaoqun et al [13]; experimental uncertainties were not provided for the data.…”

Section: Interface Characterization and Modelingmentioning

confidence: 99%

“…For this comparison, film thicknesses taken at Ca values in excess of 0.01 in the original study have been omitted; beyond this threshold, the higher aspect ratio of the channel showed strong inertial effects leading to liquid pooling in the narrow ends of the channel [13]. The film thickness measurements from the literature were obtained using an approach that relied on significant simplifying assumptions regarding bubble interface geometry, which may be responsible for the discrepancies in the comparison of the present model and the experimental data of Chaoqun et al [13]; experimental uncertainties were not provided for the data. It is important to note that no additional data for possible comparison are available in the literature specifically for actively pumped two-phase flows.…”

Section: Interface Characterization and Modelingmentioning

confidence: 99%

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Characterization of liquid film thickness in slug-regime microchannel flows

Patel

Weibel

Garimella

2017

International Journal of Heat and Mass Transfer

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An experimental investigation is conducted to examine the effects of operating conditions and channel size on the liquid film thickness of vapor bubbles in adiabatic air-water flows within the slug flow regime. Acrylic test sections are fabricated to contain a single microchannel of square cross-section with hydraulic diameters of 510 μm and 1020 μm. High-speed visualizations are used to map the flow regimes in these channels in order to determine the range of liquid and gas flow rates for which slug-regime flows are sustained. Subsequently, a tomographic optical imaging technique is employed to quantitatively reconstruct the liquid-gas interface of vapor bubbles at selected operating conditions. This technique relies on visualization of fluorescent particles seeded into the liquid phase in order to identify the phase boundaries within thin sections of the flow. Using the reconstructions, the thickness of the liquid film in the corner of the square channel cross-section is extracted. This film thickness is found to decrease with increasing capillary number, and a simple expression is proposed for calculation of the film thickness; predictions from this model match the measurements with a mean absolute error (MAE) of 21.6%; 85.7% of all predicted data points fall within an error band of ±30%. Additionally, film thickness data from the literature are compared to model predictions and a comparable MAE of 21.8% is found with 77.8% of data points falling within an error band of ±30%.

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“…Two-phase hydrodynamic characteristics in microchannels have been found to be different than those in large channels. Recent experimental studies by Ghiaasiaan and Abdel-Khalik (2000), Abdelall et al (2005), Toufik et al (2008), Kawahara et al (2002), Serizawa et al (2002), Chaoqun et al (2013), Kawahara et al (2012), Yao et al (2014) and many others tried to formulate and monitor flow in microchannels. However, there are still discrepancies in the data, mainly due to the difficulties in experimental setup and measurement.…”

Section: Introductionmentioning

confidence: 99%

An Analytical-Numerical Model for Two-Phase Slug Flow through a Sudden Area Change in Microchannels

Momen

Sherif

Lear

2016

JAFM

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In this paper, two new analytical models have been developed to calculate two-phase slug flow pressure drop in microchannels through a sudden contraction. Even though many studies have been reported on two-phase flow in microchannels, considerable discrepancies still exist, mainly due to the difficulties in experimental setup and measurements. Numerical simulations were performed to support the new analytical models and to explore in more detail the physics of the flow in microchannels with a sudden contraction. Both analytical and numerical results were compared to the available experimental data and other empirical correlations. Results show that models, which were developed based on the slug and semi-slug assumptions, agree well with experiments in microchannels. Moreover, in contrast to the previous empirical correlations which were tuned for a specific geometry, the new analytical models are capable of taking geometrical parameters as well as flow conditions into account.

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Characteristics of slug flow with inertial effects in a rectangular microchannel

Cited by 78 publications

References 52 publications

Study on the Characteristics of Bubble and Liquid Slugs for Gas-Liquid Taylor Flow in a Rectangular Micro-channel

Study on the Characteristics of Bubble and Liquid Slugs for Gas-Liquid Taylor Flow in a Rectangular Micro-channel

Characterization of liquid film thickness in slug-regime microchannel flows

An Analytical-Numerical Model for Two-Phase Slug Flow through a Sudden Area Change in Microchannels

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