scholarly journals Visualization and Measurements of Two-Phase Flows in Metallic Ducts Using Neutrons as Microscopic Probes. 5th Report. Void Distribution Measurement Method for Two-Phase Flow in a Round Tube.

1996 ◽  
Vol 62 (600) ◽  
pp. 3002-3008 ◽  
Author(s):  
Takashi HIBIKI ◽  
Kaichiro MISHIMA
Keyword(s):  
Measurement Method ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Two Phase Flows ◽  
Round Tube ◽  
Two Phase ◽  
Distribution Measurement ◽  
Void Distribution

A Combined Eulerian and Lagrangian Method for Prediction of Evaporating Sprays

2002 ◽  
Vol 124 (3) ◽  
pp. 481-488 ◽  
Author(s):  
M. Burger ◽  
G. Klose ◽  
G. Rottenkolber ◽  
R. Schmehl ◽  
D. Giebert ◽  
...  
Keyword(s):  
Two Phase Flow ◽  
Initial Conditions ◽  
Three Dimensional ◽  
Lagrangian Method ◽  
Phase Flow ◽  
Two Phase Flows ◽  
Two Phase ◽  
Lagrangian Methods ◽  
Eulerian Method ◽  
Lagrangian Modeling

Polydisperse sprays in complex three-dimensional flow systems are important in many technical applications. Numerical descriptions of sprays are used to achieve a fast and accurate prediction of complex two-phase flows. The Eulerian and Lagrangian methods are two essentially different approaches for the modeling of disperse two-phase flows. Both methods have been implemented into the same computational fluid dynamics package which is based on a three-dimensional body-fitted finite volume method. Considering sprays represented by a small number of droplet starting conditions, the Eulerian method is clearly superior in terms of computational efficiency. However, with respect to complex polydisperse sprays, the Lagrangian technique gives a higher accuracy. In addition, Lagrangian modeling of secondary effects such as spray-wall interaction enhances the physical description of the two-phase flow. Therefore, in the present approach the Eulerian and the Lagrangian methods have been combined in a hybrid method. The Eulerian method is used to determine a preliminary solution of the two-phase flow field. Subsequently, the Lagrangian method is employed to improve the accuracy of the first solution using detailed sets of initial conditions. Consequently, this combined approach improves the overall convergence behavior of the simulation. In the final section, the advantages of each method are discussed when predicting an evaporating spray in an intake manifold of an internal combustion engine.

Experimental Investigation on Flow Patterns and Frictional Pressure Drop of Downward Air-Water Two-Phase Flow in Vertical Pipes

2013 ◽  
Author(s):  
Yuqing Xue ◽  
Huixiong Li ◽  
Tianyou Sheng ◽  
Changjiang Liao
Keyword(s):  
Pressure Drop ◽  
Flow Pattern ◽  
Oil Recovery ◽  
Two Phase Flow ◽  
Flow Patterns ◽  
Phase Flow ◽  
Vertical Pipe ◽  
Two Phase Flows ◽  
Two Phase ◽  
Frictional Pressure Drop

A large amount of air need be transported into the reservoir in the deep stratum to supply oxygen to some microbes in Microbial Enhanced Oil Recovery (MEOR). Air-water two-phase flows downward along vertical pipeline during the air transportation. Base on the experiment data described in this paper, the characteristics of air-water two phase flow patterns were investigated. The flow pattern map of air-water two phase flows in the pipe with inner diameter of 65 mm was drawn, criterions of flow pattern transition were discussed, and the dynamic signals of the pressure and the differential pressure of the two phase flow were recorded to characterize the three basic flow regimes indirectly. The frictional pressure drop of downward flow in vertical pipe must not be disregarded contrast with upward two phase flow in the vertical pipe because the buoyancy must be overcame when the gas flows downward along pipe, and there would be a maximum value of frictional when the flow pattern translated from slug flow to churn flow.

B208 A Study on Multi-dimensional Behavior of Gas-Liquid Two-Phase Flow in Round Tube with Sudden Expansion Part.

2001 ◽  
Vol 2001 (0) ◽  
pp. 395-396
Author(s):  
Koichi KONDO ◽  
Kenji YOSHIDA ◽  
Tadayoshi MATSUMOTO ◽  
Tomio OKAWA ◽  
Isao KATAOKA
Keyword(s):  
Two Phase Flow ◽  
Sudden Expansion ◽  
Phase Flow ◽  
Round Tube ◽  
Two Phase

Phase Distribution Mechanisms in Turbulent Two-Phase Flow in Channels of Arbitrary Cross Section

1981 ◽  
Vol 103 (4) ◽  
pp. 583-589 ◽  
Author(s):  
D. A. Drew ◽  
R. T. Lahey
Keyword(s):  
Cross Sections ◽  
Two Phase Flow ◽  
Phase Distribution ◽  
Bubbly Flow ◽  
Arbitrary Cross Section ◽  
Phase Flow ◽  
Two Phase ◽  
Void Distribution ◽  
Special Case ◽  
Turbulent Two Phase Flow

An analytical model for the phase distribution mechanisms in fully developed turbulent two-phase flow in channels of arbitrary cross sections has been derived. The model has been applied to the special case of cylindrical pipe flow, and compared with existing data. It has been found that, for bubbly flow, it is the distribution of the liquid phase turbulence which determines the void distribution. Furthermore, the void distribution depends on the anisotropic nature of the turbulent two-phase flow.

Correlations of the Holdup and the Frictional Pressure Drop in Air-Water Two-Phase Flow in a Flat Capillary Rectangular Channel

2004 ◽  
Author(s):  
Hideo Ide ◽  
Tohru Fukano
Keyword(s):  
Pressure Drop ◽  
Aspect Ratio ◽  
Two Phase Flow ◽  
Rectangular Channel ◽  
Flow Characteristics ◽  
Phase Flow ◽  
Two Phase Flows ◽  
Two Phase ◽  
Frictional Pressure Drop ◽  
Flow Phenomena

Both vertical upward and horizontal gas-liquid two-phase flows in a flat capillary rectangular channel were studied to clarify the flow phenomena, the holdup and the frictional pressure drop. The dimension of the channel used was 9.9 mm × 1.1 mm. The orientations of the channel were with the wide side vertical and the wide side horizontal. The differences between the flow characteristics in such orientations were investigated. New correlations of holdup and frictional pressure drop for flat capillary channels are proposed, in which the effect of aspect ratio has been taken into consideration.

Flow-Induced Vibration Model for Steam Generator Tubes in Two-Phase Flow

2008 ◽  
Author(s):  
Njuki W. Mureithi ◽  
Soroush Shahriary ◽  
Michel J. Pettigrew
Keyword(s):  
Force Field ◽  
Steam Generator ◽  
Two Phase Flow ◽  
Operating Conditions ◽  
Phase Flow ◽  
Two Phase Flows ◽  
Two Phase ◽  
Fluid Force ◽  
Vibration Stability ◽  
Steam Generator Tubes

While steam generators operate in two-phase flow, the complex nature of the flow makes the prediction of flow-induced fluidelastic instability of steam generator tubes a challenging problem yet to be solved. In the work reported here, the quasi-static fluid force-field, which is the important unknown for two-phase flows, is measured in a rotated-triangle tube bundle for a series of void fractions and flow velocities. The forces are shown to be strongly dependent on void fraction, flow rates and relative tube positions. The fluid force field is then employed along with quasi-steady vibration stability models, originally developed for single phase flows, to model the two-phase flow problem and predict the critical instability velocity. The results are compared with dynamic vibration stability tests and are shown to be in good agreement. The present work uncovers some of the complexities of the fluid force field in two-phase flows. The database provides new potential to designers to estimate expected fluid dynamic loads under operating conditions. The force field data may also be applied in dynamic computations for tube wear simulations, replacing the simple Connors’ model which is currently used.

Numerical Simulation for Two-Phase Flows in Fuel Cell Minichannels

2011 ◽  
Vol 8 (4) ◽  
Author(s):  
Jean-Baptiste Dupont ◽  
Dominique Legendre ◽  
Anna Maria Morgante
Keyword(s):  
Fuel Cell ◽  
Numerical Simulations ◽  
Two Phase Flow ◽  
Numerical Code ◽  
Experimental Investigations ◽  
Pressure Jump ◽  
Phase Flow ◽  
Two Phase Flows ◽  
Two Phase ◽  
Flow Configurations

This work presents direct numerical simulations of two-phase flows in fuel cell minichannels. Different two-phase flow configurations can be observed in such minichannels, which depend on gas-flow rate, liquid holdup, and wettability of each wall. These flows are known to have a significant impact on the fuel cell’s performance. The different two-phase flow configurations must be studied specially concerning the prediction of the transition among them. In the fuel cell minichannels, experimental investigations are difficult to perform because of the small size of the device and the difficult control of the wettability properties of the walls. In such systems, numerical approach can provide useful information with a perfect control of the flow characteristics, particularly for the wettability aspect. The numerical code used in this study is the JADIM code developed at IMFT, which is based on a “volume of fluid” method for interface capturing without any interface reconstruction. The numerical description of the surface tension is one of the crucial points in studying such systems where capillary effects control the phase distribution. The static and the dynamics of the triple line between the liquid, the gas, and the wall is also an essential physical mechanism to consider. The numerical implementation of this model is validated in simple situations where analytical solutions are available for the shape and the pressure jump at the interface. In this paper we present the characteristics of the JADIM code and its potential for the studies of the fuel cell internal flows. Numerical simulations on the two-phase flows on walls, in corners, and inside channels are shown.

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