EXPERIMENTAL DATA SET NO. 25: PHASE DISTRIBUTION AND TWO-PHASE TURBULENCE FOR BUBBLY FLOWS IN PIPES

1992 ◽  
Vol 6 (1-4) ◽  
pp. 303-349
Author(s):  
S. J. Lee
Keyword(s):  
Experimental Data ◽  
Phase Distribution ◽  
Bubbly Flows ◽  
Two Phase ◽  
Data Set

EXPERIMENTAL DATA SET NO. 24: PHASE DISTRIBUTION IN BUBBLY FLOW

1992 ◽  
Vol 6 (1-4) ◽  
pp. 257-301 ◽  
Author(s):  
Akimi Serizawa ◽  
Isao Kataoka ◽  
Itaru Michiyoshi
Keyword(s):  
Experimental Data ◽  
Phase Distribution ◽  
Bubbly Flow ◽  
Data Set

Bubble size and system pressure effects on the phase distribution for two-phase turbulent bubbly flows

2001 ◽  
Vol 215 (1) ◽  
pp. 121-132 ◽  
Author(s):  
T-C Kuo ◽  
A-S Yang ◽  
C-C Chieng
Keyword(s):  
High Pressure ◽  
Void Fraction ◽  
Bubble Size ◽  
Phase Distribution ◽  
Pressure Effects ◽  
Bubbly Flows ◽  
Two Phase ◽  
System Pressure ◽  
Transport Behaviour ◽  
Pressure Transport

The coupled Eulerian-Lagrangian approach was used to study the effects of bubble size and high-pressure transport behaviour on the phase distribution mechanisms in vertically upward air-water two-phase bubbly flows. The approach solves the conservation equations of liquid phase in Eulerian space and equations of motion in conjunction with the random walk method for dispersed air bubbles in Lagrangian space. Numerical calculations were performed under conditions of three bubble diameters (2.8, 4.0 and 5.0 mm) and two different pressure levels (0.1 and 7.17 MPa) to explore the flow and void fraction development phenomena. Simulation results indicate the tendency of higher slip ratios and the movement of the void fraction peak towards the flow core for larger gas bubbles. In the pressure range 0.1-7.17 MPa, predictions reveal that the effect of high-pressure transport behaviour on the phase distribution is insignificant.

scholarly journals Calculation of critical heat transfer in horizontal evaporator pipes in cooling systems of high-rise buildings

2018 ◽  
Vol 33 ◽  
pp. 02037 ◽  
Author(s):  
Andrey Aksenov ◽  
Anna Malysheva
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Two Phase Flow ◽  
Phase Distribution ◽  
Experimental Studies ◽  
Phase Flow ◽  
Two Phase ◽  
High Rise ◽  
Refrigeration Equipment ◽  
Order Of Magnitude

An exact calculation of the heat exchange of evaporative surfaces is possible only if the physical processes of hydrodynamics of two-phase flows are considered in detail. Especially this task is relevant for the design of refrigeration supply systems for high-rise buildings, where powerful refrigeration equipment and branched networks of refrigerants are used. On the basis of experimental studies and developed mathematical model of asymmetric dispersed-annular flow of steam-water flow in horizontal steam-generating pipes, a calculation formula has been obtained for determining the boundaries of the zone of improved heat transfer and the critical value of the heat flux density. A new theoretical approach to the solution of the problem of the flow structure of a two-phase flow is proposed. The applied method of dissipative characteristics of a two-phase flow in pipes and the principle of a minimum rate of entropy increase in stabilized flows made it possible to obtain formulas that directly reflect the influence of the viscous characteristics of the gas and liquid media on their distribution in the flow. The study showed a significant effect of gravitational forces on the nature of the phase distribution in the cross section of the evaporative tubes. At a mass velocity of a two-phase flow less than 700 kg / m2s, the volume content of the liquid phase near the upper outer generating lines of the tube is almost an order of magnitude lower than the lower one. The calculation of the heat transfer crisis in horizontal evaporative tubes is obtained. The calculated dependence is in good agreement with the experimental data of the author and a number of foreign researchers. The formula generalizes the experimental data for pipes with the diameter of 6-40 mm in the pressure of 2-7 MPa.

Progress on Prediction of Bubbly Flows Around Ships

2016 ◽  
Author(s):  
J. Li ◽  
A. M. Castro ◽  
P. M. Carrica
Keyword(s):  
Experimental Data ◽  
Size Distribution ◽  
Two Phase Flow ◽  
Fluid Model ◽  
Bubbly Flows ◽  
Phase Flow ◽  
Flat Bottom ◽  
Two Phase ◽  
Practical Applications ◽  
Bubble Entrainment

This paper presents recent progress on prediction of bubbly flows around ships, including bubble entrainment modeling, bubble transport and numerical issues. The bubbly flow is described by a polydisperse two-fluid model that can predict the bubble entrainment locations and rates, bubble dissolution, breakup and coalescence rates, bubble velocities, turbulence quantities and bubble size distribution. To test the performance of the two phase flow model, several simulations are conducted on canonical bubbly flows with wave breaking. These well experimentally studied flows provide important information for the design of the bubble entrainment model, which is the weakest link in the model chain but crucial for prediction of the bubbly wake. The results are compared with experimental data to study the model’s accuracy and to calibrate the entrainment model constants. Full scale simulations for the flat bottom Kann boat and the Athena R/V are performed to evaluate the model under more complex flows of naval relevance that have considerable data available. It is found that the model calibrated with canonical problems predicts good results for Athena R/V, but the current turbulent entrainment model significantly underestimates the entrainment at the bow of Kann boat due to other entrainment mechanisms involved (entrainment due to impact, droplets, etc.). The breakup model, which currently considers turbulent mechanisms, underestimates the population of small bubbles in the boundary layer where strong shear is present. Finally, a grid study is carried on Athena R/V to test grid convergence. Void fraction and size distribution are compared against available experimental data and discussed in detail. Overall, the simulations show encouraging results considering the complexity of two phase flow involved in ship applications, and the model is proven to be grid independent, a very important property for practical applications.

Simulation of Surfactant/Polymer Floods With a Predictive and Robust Microemulsion Flash Calculation

SPE Journal ◽  
2016 ◽  
Vol 22 (02) ◽  
pp. 470-479 ◽  
Author(s):  
Saeid Khorsandi ◽  
Changhe Qiao ◽  
Russell T. Johns
Keyword(s):  
Experimental Data ◽  
Phase Behavior ◽  
Oil Recovery ◽  
Carbon Number ◽  
General Purpose ◽  
Accurate Estimation ◽  
Chemical Flooding ◽  
Two Phase ◽  
Data Set ◽  
Average Curvature

Summary A compositional reservoir simulator that uses a predictive microemulsion phase-behavior model is essential for accurate estimation of oil recovery from surfactant/polymer (SP) floods. Current chemical-flooding simulators, however, use Hand's model (Hand 1939) for phase-behavior calculation. Hand's model can reasonably fit a limited set of experimental data, such as those of a salinity scan, but because it is empirical, it cannot predict phase behavior outside the matched data set. Hydrophyllic/lypophyllic difference (HLD) and net-average-curvature (NAC) equation of state (EOS) (Acosta et al. 2003) has shown great performance for tuning and prediction of experimental data. In this paper, the EOS model with the extension to two-phase regions has been incorporated for the first time into UTCHEM (2000) and our in-house general-purpose compositional simulator, PennSim (2013). All Winsor regions (Type II−, II+, III, and IV) are modeled by use of a consistent physics-based EOS model without the need for Hand's approach. The new simulator is therefore able to account correctly for gridblock properties, which can vary temporally and spatially, and significantly improve the modeling of phase behavior and oil recovery. The results show excellent agreement between UTCHEM and PennSim both in composition space and for composition/saturation profiles for the 1D simulation. The effects of varying pressure, temperature, equivalent alkane carbon number (EACN), and salinity on recoveries are demonstrated also in 1D simulations.

Effect of Gravity on Axial Development of Phase Distribution Patterns in Bubbly Two-Phase Flow

2009 ◽  
Author(s):  
Takashi Nishioji ◽  
Taichi Kato ◽  
Yutaka Fukuhara ◽  
Tatsuya Hazuku ◽  
Tomoji Takamasa ◽  
...  
Keyword(s):  
Two Phase Flow ◽  
Phase Distribution ◽  
Bubble Diameter ◽  
Distribution Patterns ◽  
Stereo Image ◽  
Bubbly Flows ◽  
Phase Flow ◽  
Two Phase ◽  
Microgravity Conditions ◽  
Axial Development

The axial development of the void fraction profile, interfacial area concentration and Sauter mean bubble diameter of adiabatic nitrogen-water bubbly flows in a 9 mm-diameter pipe were measured using stereo image processing in normal and microgravity conditions. The effect of gravity and flow conditions on the radial distribution of bubbles and the axial development of the two-phase flow parameter is discussed in detail based on the obtained data. By taking into account normalized parameters based on void peak fraction and void peak intensity in the pipe cross-section, the phase distribution patterns were classified into three types: a wall peak, a core peak and an intermediate peak. Phase distribution pattern maps are presented for vertical upward bubbly flows in normal and microgravity conditions.

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