Liquid-Liquid Two-Phase Flow Patterns and Mass Transfer Characteristics in a Circular Microchannel

2012 ◽  
Vol 482-484 ◽  
pp. 89-94
Author(s):  
Xu Bin Zhang ◽  
Dan Chen ◽  
Yan Wang ◽  
Wang Feng Cai
Keyword(s):  
Mass Transfer ◽  
Annular Flow ◽  
Flow Patterns ◽  
Immiscible Fluids ◽  
Viscous Force ◽  
Inertia Force ◽  
Transfer Coefficients ◽  
Two Phase ◽  
Transfer Characteristics ◽  
Circular Microchannel

In this paper, flow patterns and mass transfer characteristics of two immiscible fluids in a T-junction circular microchannel were investigated. Four flow patterns, i.e. slug flow, irregular flow, parallel flow and annular flow, were captured by a CCD method, which were resulted from the competition among interfacial tension, viscous force and inertia force. Besides, the overall volumetric mass transfer coefficients ka for the four flow patterns was determined experimentally. The values of ka are in the range of 0.006~0.545s−1 and mainly dependent on the superficial velocity and the flow pattern regime.

scholarly journals Liquid–liquid two-phase flow patterns and mass transfer characteristics in rectangular glass microreactors

2008 ◽  
Vol 63 (16) ◽  
pp. 4035-4044 ◽  
Author(s):  
Anne-Laure Dessimoz ◽  
Laurent Cavin ◽  
Albert Renken ◽  
Lioubov Kiwi-Minsker
Keyword(s):  
Mass Transfer ◽  
Two Phase Flow ◽  
Flow Patterns ◽  
Phase Flow ◽  
Two Phase ◽  
Transfer Characteristics ◽  
Rectangular Glass

scholarly journals Two-Phase Flow Mass Transfer Analysis of Airlift Pump for Aquaculture Applications

Fluids ◽  
2021 ◽  
Vol 6 (6) ◽  
pp. 226
Author(s):  
Rashal Abed ◽  
Mohamed M. Hussein ◽  
Wael H. Ahmed ◽  
Sherif Abdou
Keyword(s):  
Mass Transfer ◽  
Oxygen Transfer ◽  
Transfer Rate ◽  
Two Phase Flow ◽  
Oxygen Transfer Rate ◽  
Flow Patterns ◽  
Oxygen Mass Transfer ◽  
Phase Flow ◽  
Two Phase ◽  
Airlift Pump

Airlift pumps can be used in the aquaculture industry to provide aeration while concurrently moving water utilizing the dynamics of two-phase flow in the pump riser. The oxygen mass transfer that occurs from the injected compressed air to the water in the aquaculture systems can be experimentally investigated to determine the pump aeration capabilities. The objective of this study is to evaluate the effects of various airflow rates as well as the injection methods on the oxygen transfer rate within a dual injector airlift pump system. Experiments were conducted using an airlift pump connected to a vertical pump riser within a recirculating system. Both two-phase flow patterns and the void fraction measurements were used to evaluate the dissolved oxygen mass transfer mechanism through the airlift pump. A dissolved oxygen (DO) sensor was used to determine the DO levels within the airlift pumping system at different operating conditions required by the pump. Flow visualization imaging and particle image velocimetry (PIV) measurements were performed in order to better understand the effects of the two-phase flow patterns on the aeration performance. It was found that the radial injection method reached the saturation point faster at lower airflow rates, whereas the axial method performed better as the airflow rates were increased. The standard oxygen transfer rate (SOTR) and standard aeration efficiency (SAE) were calculated and were found to strongly depend on the injection method as well as the two-phase flow patterns in the pump riser.

Heat Transfer on Nanofluid Flow With Homogeneous–Heterogeneous Reactions and Internal Heat Generation

2014 ◽  
Vol 136 (12) ◽  
Author(s):  
Raj Nandkeolyar ◽  
Peri K. Kameswaran ◽  
Sachin Shaw ◽  
Precious Sibanda
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Heat Generation ◽  
Internal Heat ◽  
Internal Heat Generation ◽  
Heterogeneous Reactions ◽  
Transfer Coefficients ◽  
Transfer Characteristics ◽  
Fluid Properties

We investigated heat and mass transfer on water based nanofluid due to the combined effects of homogeneous–heterogeneous reactions, an external magnetic field and internal heat generation. The flow is generated by the movement of a linearly stretched surface, and the nanofluid contains nanoparticles of copper and gold. Exact solutions of the transformed model equations were obtained in terms of hypergeometric functions. To gain more insights regarding subtle impact of fluid and material parameters on the heat and mass transfer characteristics, and the fluid properties, the equations were further solved numerically using the matlab bvp4c solver. The similarities and differences in the behavior, including the heat and mass transfer characteristics, of the copper–water and gold–water nanofluids with respect to changes in the flow parameters were investigated. Finally, we obtained the numerical values of the skin friction and heat transfer coefficients.

Lyon-Type Integral Forms of Wall Friction, Heat- and Mass Transfer Closure Relationships for Non-Equilibrium Two-Phase Flows: Generalization for Annular and Rod Cluster Geometries

2013 ◽  
Author(s):  
Yuri Kornienko
Keyword(s):  
Boundary Layer ◽  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Constitutive Relations ◽  
Wall Friction ◽  
Transfer Coefficients ◽  
Two Phase ◽  
Friction Heat ◽  
Integral Forms ◽  
Substance Transfer

The main goal of this paper is to describe new approach to constructing generalized closure relationships for pipe, annular and sub-channel transfer coefficients for wall friction, heat and mass transfer. The novelty of this approach is that it takes into account not only axial and transversal parameter distributions, but also an azimuthal substance transfer effects. These constitutive relations, which are primordial in the description of single- and two-phase one-dimensional (1D) flow models, can be derived from the initial 3D drift flux formulation. The approach is based on the Reynolds flow, boundary layer, and substance transfer generalized coefficient concepts. Another aim is to illustrate the validity of the “conformity principle” for the limiting cases. The method proposed in this paper is founded on the similarity theory, boundary layer model, and a phenomenological description of the regularity of the substance transfer (momentum, heat, and mass) as well as on an adequate simulation of the flow structures. With the proposed generalized approach it becomes possible to develop an integrated in form and semi-empirical in maintenance structure analytical relationships for wall friction, heat and mass transfer coefficients.

Flow Characteristics of Adiabatic Gas-Liquid Two-Phase Flow in a Horizontal Flat Rectangular Microchannel

2011 ◽  
Author(s):  
Hideo Ide ◽  
Kentaro Satonaka ◽  
Tohru Fukano
Keyword(s):  
Void Fraction ◽  
Slug Flow ◽  
Annular Flow ◽  
Two Phase Flow ◽  
Flow Characteristics ◽  
Flow Patterns ◽  
Phase Flow ◽  
Similar Data ◽  
Two Phase ◽  
The Mean

Experiments were performed to obtain, analyze and clarify the mean void fraction, the mean liquid holdup, and the liquid slug velocity and the air-water two-phase flow patterns in horizontal rectangular microchannels, with the dimensions equal to 1.0 mm width × 0.1 mm depth, and 1.0 mm width × 0.2 mm depth, respectively. The flow patterns such as bubble flow, slug flow and annular flow were observed. The microchannel data showed similar data patterns compared to those in minichannels with the width of 1∼10mm and the depth of 1mm which we had previously reported on. However, in a 1.0 × 0.1 mm microchannel, the mean holdup and the base film thickness in annular flow showed larger values because the effects of liquid viscosity and surface tension on the holdup and void fraction dominate. The remarkable flow characteristics of rivulet flow and the flow with a partial dry out of the channel inner wall were observed in slug flow and annular flow patterns in the microchannel of 0.1 mm depth.

Flow Boiling Visualization of R-134a in a Vertical Channel of Small Diameter

2007 ◽  
Author(s):  
Claudi Marti´n-Callizo ◽  
Bjo¨rn Palm ◽  
Wahib Owhaib ◽  
Rashid Ali
Keyword(s):  
Flow Pattern ◽  
Annular Flow ◽  
Two Phase Flow ◽  
Flow Boiling ◽  
Bubbly Flow ◽  
Flow Patterns ◽  
Phase Flow ◽  
Two Phase ◽  
R 134A ◽  
Heated Length

The present work reports on flow boiling visualization of refrigerant R-134a in a vertical circular channel with internal diameter of 1.33 mm and 235 mm in heated length. Quartz tube with a homogeneous ITO-coating is used allowing heating and simultaneous visualization. Flow patterns have been observed along the heated length with the aid of a digital camera with close-up lenses. From the flow boiling visualization, seven distinct two-phase flow patterns have been observed: Isolated bubbly flow, confined bubbly flow, slug flow, churn flow, slug-annular flow, annular flow, and mist flow. Two-phase flow pattern observations are presented in the form of flow pattern maps. Finally, the experimental flow pattern map is compared to models developed for conventional sizes as well as to a microscale map for air-water mixtures available in the literature, showing a large discrepancy.

Thermoreflectance Wall Temperature Measurement in Annular Two-Phase Flow

2019 ◽  
Author(s):  
Jason Chan ◽  
Brian E. Fehring ◽  
Roman W. Morse ◽  
Kristofer M. Dressler ◽  
Gregory F. Nellis ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Wall Temperature ◽  
Annular Flow ◽  
High Heat ◽  
High Heat Flux ◽  
Phase Flow ◽  
Transfer Coefficients ◽  
Two Phase ◽  
Heat Transfer Coefficients ◽  
Dry Out

Abstract A thermoreflectance method to measure wall temperature in two-phase annular flow is described. In high heat flux conditions, momentary dry-out occurs as the liquid film vaporizes, resulting in dramatic decreases in heat transfer coefficient. Simultaneous liquid and vapor thermoreflectance measurements allow calculations of instantaneous and time-averaged heat transfer coefficients. Validation, calibration and uncertainty of the technique are discussed.

Effects of Fin Shapes and Arrangements on Heat Transfer for Impingement/Effusion Cooling With Crossflow

2005 ◽  
Author(s):  
Sung Kook Hong ◽  
Dong-Ho Rhee ◽  
Hyung Hee Cho
Keyword(s):  
Mass Transfer ◽  
Heat Mass Transfer ◽  
Flow Characteristics ◽  
Local Heat ◽  
Wall Jet ◽  
Transfer Coefficients ◽  
Mass Transfer Coefficients ◽  
Blowing Ratio ◽  
Transfer Characteristics ◽  
Sublimation Method

The present paper has investigated the effects of fin on the flow and heat/mass transfer characteristics for the impingement/effusion cooling with crossflow. The fins of circular or rectangular shape are installed between two perforated plates and the crossflow passes between these two plates. The blowing ratio is changed from 0.5 to 1.5 for a fixed jet Reynolds number of 10,000. A naphthalene sublimation method is used to obtain the local heat/mass transfer coefficients on the effusion plate. A numerical calculation is also performed to investigate the flow characteristics. Flow and heat/mass transfer characteristics are changed significantly due to installation of fins. In the injection region, wall jet spreads more widely than the case without fins because fin prevents the wall jet from being swept away by the crossflow. In the effusion region, higher heat/mass transfer coefficient is obtained due to the flow disturbance and acceleration by the fin. As the blowing ratio increases, the effects of fin against the crossflow become more significant and then the higher average heat/mass transfer coefficients are obtained. Especially, the cases with rectangular fins have about 40%∼45% enhancement at the high blowing ratio of M = 1.5. However, the increase of blockage effect gives more pressure loss in the channel.

scholarly journals Investigations of mass transfer in annular gas-liquid flow in a microreactor

2016 ◽  
Vol 37 (1) ◽  
pp. 55-64 ◽  
Author(s):  
Paweł Sobieszuk ◽  
Karolina Napieralska
Keyword(s):  
Mass Transfer ◽  
Cross Section ◽  
Chemical Reaction ◽  
Liquid Flow ◽  
Annular Flow ◽  
Gas Flow ◽  
Absorption Rate ◽  
Transfer Coefficients ◽  
Water Solutions ◽  
Gas Liquid Flow

Abstract The paper presents an investigation of mass transfer in gas-liquid annular flow in a microreactor. The microreactor had a meandered shape with a square cross-section of the channel (292×292 μm, hydraulic diameter 292 μm) and 250 mm in length. The rate of CO2 absorption from the CO2/N2 mixture in NaOH (0.1 M, 0.2 M, 0.7 M, 1.0 M and 1.5 M) water solutions was measured. Two velocities of gas flow and two velocities of liquid flow were used. In two cases a fully developed annular flow at the beginning of the channel was observed, whilst in two cases annular flow was formed only in about 2/3 of the microchannel length. Based on the measurements of CO2 absorption rate, the values of volumetric liquid - side mass transfer coefficients with the chemical reaction were determined. Then physical values of coefficients were found. Obtained results were discussed and their values were compared with the values predicted by literature correlations.

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