CFD Modelling for Gas-Liquid and Liquid-Liquid Taylor Flows in the Entrance Region of Microchannels

2021 ◽  
Author(s):  
Amin Etminan ◽  
Yuri S. Muzychka ◽  
Kevin Pope
Keyword(s):  
Liquid Flow ◽  
Continuous Flow ◽  
Velocity Ratio ◽  
Time History ◽  
Simulation Method ◽  
Cfd Modelling ◽  
Cross Sectional ◽  
Systematic Analysis ◽  
Gas Liquid Flow ◽  
The Moment

Abstract This paper presents a CFD-based simulation method for air/water and water/dodecane Taylor flows through an axisymmetric microchannel with a circular cross-sectional area. A systematic analysis is conducted by exploring the effects of different superficial velocities and apparent viscosities on the hydrodynamics of a slug flow regime. A concentric junction is employed to make bubbles of air in a continuous flow of water and slugs of water in a continuous flow of dodecane oil. A time-history study is conducted to predict the air-bubble and water-slug evolution processes, in particular at the moment of slug breakup. The results show that the larger apparent viscosity ratio of phases involved in the liquid-liquid flow generates a more stable interface. However, the liquid slug length is less and film thickness is slightly larger in liquid-liquid compared to gas-liquid flow. Furthermore, variations in gas and liquid holdups are correlated by the superficial velocity ratio. The numerical analysis developed in this paper is in good agreement with the correlations and data in the literature.

scholarly journals Comparison of Gas–Liquid Flow Characteristics in Geometrically Different Swirl Generating Devices

Energies ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4653 ◽  
Author(s):  
Ryan Anugrah Putra ◽  
Martin Neumann-Kipping ◽  
Thomas Schäfer ◽  
Dirk Lucas
Keyword(s):  
Liquid Flow ◽  
Gamma Ray ◽  
Double Helix ◽  
Flow Characteristics ◽  
Cross Sectional ◽  
Euler Model ◽  
Gas Liquid Flow ◽  
Gas Volume ◽  
Gamma Ray Computed Tomography ◽  
Blade Element

The gas–liquid flow characteristics for blade, single, and the double-helical swirl elements were numerically investigated and compared in this work. The Euler–Euler model assuming bi-modal bubble size distributions was used. The experiment, conducted in a vertical pipe equipped with a static blade swirl element, was used as the basis for the computational fluid dynamics (CFD) simulations. In the experiment, high-resolution gamma-ray computed tomography (HireCT) was used to measure the gas volume fractions at several planes within the blade swirl element. The resulting calculated profiles of the pressure, liquid and gas velocities as well as the gas fraction showed a large influence of the swirl elements’ geometry. The evolution and characteristics of the calculated gas–liquid phase distributions in different measurement planes were found to be unique for each type of swirl element. A single gas core in the center of the pipe was observed from the simulation of the blade element, while multiple cores were observed from the simulations of the single and double helix elements. The cross-sectional gas distribution downstream of the single and double helical elements changed drastically within a relatively short distance downstream of the elements. In contrast, the single gas core downstream of the blade element was more stable.

Modeling the Onset of Gas Entrainment in a Reduced T-Junction With Co-Current Stratified Gas-Liquid Flow

2012 ◽  
Vol 134 (8) ◽  
Author(s):  
Robert C. Bowden ◽  
Ibrahim G. Hassan
Keyword(s):  
Liquid Flow ◽  
Three Dimensional ◽  
Flow Distribution ◽  
Critical Height ◽  
Cross Sectional ◽  
Gas Entrainment ◽  
Mass Fluxes ◽  
Height Prediction ◽  
Dip Angle ◽  
Gas Liquid Flow

A model was developed to predict the onset of gas entrainment in a single downward oriented branch. The branch was installed on a horizontal square cross-sectional channel having a smooth stratified co-currently flowing gas-liquid regime in the inlet region. The branch flow was simulated as a three-dimensional point-sink while the run flow was treated as a uniform velocity at the critical dip. Experiments were performed to determine the critical liquid flow distribution between the run and the branch. A correlation was developed relating the branch Froude number to the ratio of the superficial liquid mass fluxes in the run and the branch. The correlation was used as a boundary condition in the model. A methodology was developed using digital imaging to record the coordinates of the critical dip at the onset of as entrainment. The dip angle was found to range between 40 to 60 degrees and constant dip angles of 40, 50 and 60 degrees were selected as boundary conditions. The critical height was predicted to within 50% of experiments with the error attributed to differences in the modeled and experimental geometries. A semi-empirical analysis using the experimental geometry yielded a critical height prediction to within 20% of experimental results.

scholarly journals Measuring the Continuity of a Gas-Liquid Flow in a Pipeline

2021 ◽  
Vol 2091 (1) ◽  
pp. 012042
Author(s):  
G N Akhobadze
Keyword(s):  
Electromagnetic Wave ◽  
Electric Field ◽  
Liquid Flow ◽  
Isotropic Medium ◽  
Open Resonator ◽  
Measuring Instruments ◽  
Cross Sectional ◽  
Instrument Making ◽  
Study Results ◽  
Gas Liquid Flow

Abstract The principles of building a meter for the continuity of gas-liquid flows in pipelines have been proposed, based on the polarized electromagnetic wave characteristics. A two-component flow in a pipeline has been analyzed considering the cross-sectional area of the flow in the pipeline. The judgment about the flow continuity by the phase difference between the electromagnetic fields polarized parallel and perpendicular to the wave propagation direction has been justified. The naturally and artificially anisotropic flow continuity measuring study results are given. A polarization technique of electromagnetic wave birefringence in the isotropic medium has been considered, based on placing an isotropic medium in an electric field formed by two capacitor electrodes. The possibility of eliminating the parameter measuring errors induced by temperature impact on the electromagnetic wave refractive index in controlled media is shown based on two electrodes of a capacitor creating an electric field in the dielectric pipeline measuring section as an option for implementing flat reflectors of an open resonator. The study results can be used in the instrument-making industry in the development and implementation of smart contactless measuring instruments in the gas-liquid flow analysis and control.

Gas–liquid flow in a 2D column: Comparison between experimental data and CFD modelling

2001 ◽  
Vol 56 (21-22) ◽  
pp. 6367-6383 ◽  
Author(s):  
Peter Spicka ◽  
Madalena M. Dias ◽  
Jose’e Carlos B. Lopes
Keyword(s):  
Experimental Data ◽  
Liquid Flow ◽  
Cfd Modelling ◽  
Gas Liquid Flow ◽  
Column Comparison

CFD modelling of gas–liquid flow in an industrial scale gas-stirred leaching tank

2015 ◽  
Vol 142 ◽  
pp. 63-72 ◽  
Author(s):  
Tao Song ◽  
Kaixi Jiang ◽  
Junwu Zhou ◽  
Deyu Wang ◽  
Ning Xu ◽  
...  
Keyword(s):  
Liquid Flow ◽  
Industrial Scale ◽  
Cfd Modelling ◽  
Gas Liquid Flow

Hubungan Antara Menyusui Dengan Involusi Uterus Pada Ibu Nifas Fisiologis Di RSIA Aura Syifa Kabupaten Kediri

1970 ◽  
Vol 5 (2) ◽  
pp. 64
Author(s):  
Eny Sendra ◽  
Dewi Indriani
Keyword(s):  
Breast Feeding ◽  
Sampling Technique ◽  
Chi Square ◽  
Cross Sectional ◽  
Fisher Test ◽  
Key Word ◽  
Chi Square Test ◽  
The Moment

Breast feeding is giving milk to be drunk to the baby from the breast. Uterus involution is a process how the uterus return to the condition back, before pregnanting after bearing. At the moment of suckling, happens a stimulus and brings the hormones out, such as oksitosin uses not only to stimulate some muscles constraction but also to stimulate the uterus, so that the process of uterus involution happens foster. According to the explanations above, the research aimed to know about the correlation between breast feeding and uterus involution. This research’s design was, cross sectional by the population of all childbirth mothers approximately 50 persons / month. By using accidental sampling technique we got 21 sample respondents. The place of research in RSIA Aura Syifa in Kediri Regency on 16th until 22nd of June 2009. From this research’s result, we got 14 persons (66,67%) with normal uterus involution, suckled in a good way, one person (4,67%) with normal uterus involution, suckled in a wrong way, 2 persons (9,52%) with abnormal uterus involution, suckled in a good way and 4 persons (19,05%) with abnormal uterus involution, suckled in a wrong way. Statistic test which used chi-square test, counted the probability frequency in advance, from that we got 3 columns with the score, less than 5, so that chi-square can not be continued and by doing exact fisher test, the score was 0,001. Because P with the grade mistake 0,05 smaller, so the conclusion was “Ho” is rejected, it meant “there was correlation between suckling and uterus involution”. Key Word : Breast feeding, uterus involution

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