scholarly journals Correlative Mapping Method for Measuring Individual Phase Flow Rates in Air-Water Two-Phase Flow Based on Stochastic Features.

1998 ◽  
Vol 41 (4) ◽  
pp. 863-870 ◽  
Author(s):  
Kiyoshi MINEMURA ◽  
Takeaki TAKEOKA ◽  
Shinji SYODA ◽  
Kazuyuki EGASIRA ◽  
Yutaka OGAWA
1997 ◽  
Vol 63 (612) ◽  
pp. 2707-2712
Author(s):  
Kiyoshi MINEMURA ◽  
Takeaki TAKEOKA ◽  
Shinji SHODA ◽  
Kazuyuki EGASHIRA ◽  
Yutaka OGAWA

Author(s):  
Tomomi Uchiyama ◽  
Hirokazu Tominaga ◽  
Kiyoshi Minemura

This study proposes a measuring method for the individual phase flow rates of gas-liquid two-phase mixtures flowing through a pipe. First, the time-variations for pressure are measured at three points around a vortex generator mounted in the pipe under the known flow rates. Secondly, the stochastic features of the differential pressure fluctuations, such as the mean and the standard deviation, are calculated to construct a database relating the flow rates with the stochastic features. Consequently, if the differential pressure fluctuations are measured under unknown flow rates, the individual phase flow rates are successfully identified from the database. A neural network is employed for the identification. This study also applies the proposed method for the measurement of air-water two-phase flow and discusses the measured results.


2006 ◽  
Vol 84 (1) ◽  
pp. 40-53 ◽  
Author(s):  
S.M. Richardson ◽  
G. Saville ◽  
S.A. Fisher ◽  
A.J. Meredith ◽  
M.J. Dix

1997 ◽  
Vol 23 (5) ◽  
pp. 624-627
Author(s):  
Toshiro Tsuji ◽  
Toshiharu Shibata ◽  
Osamu Uemaki ◽  
Hironori Itoh

Author(s):  
DuWayne Schubring ◽  
Rory E. Foster ◽  
Timothy A. Shedd

Cross-sectional thin film micro-particle image velocimetry (cTFMPIV) analysis has been performed for air-water two-phase flow in a 19.05 mm horizontal duct. Images were captured by introducing a light sheet from a Nd:YAG laser into the flow, with the fluorescent emissions from three micron particles captured by a CCD camera behind a microscope objective and red filter. These images were grouped into pairs and digitally enhanced to isolate particle traces using commercial image processing software. Image pairs were collected for five air flow rates at each of four water flow rates and separated into base film and wave zones for PIV analysis. Using DaVis 7.1 (LaVision GmbH), vector maps were obtained for each pair. Less than 2% of the image pairs were removed due to clearly spurious vectors, while the appropriate zone for less than 8% of the image pairs could not be determined These pairs were grouped into a third batch. The vector maps were analyzed to calculate velocity profiles and turbulence (fluctuation) statistics in terms of wall coordinates. These statistics included intensities and Reynolds stresses. The base film shows laminar behavior beyond what would be expected from the universal velocity profile. The wave zone displays significantly different behavior and appears to reach an asymptote rapidly. Calculation of fluctuation intensities indicates a maximum within the wave zone along the gas-liquid interface, while the distribution of radial fluctuations in the base film and axial turbulence in all zones is approximately uniform. Calculation of the u′v′ shear Reynolds stress suggests that it has a negative value.


Author(s):  
Julie E. Steinbrenner ◽  
Eon Soo Lee ◽  
Fu-Min Wang ◽  
Chen Fang ◽  
Carlos H. Hidrovo ◽  
...  

An important function of the gas delivery channels in Proton Exchange Membrane (PEM) fuel cells is the evacuation of liquid water created at the cathode. The resulting two-phase flow can become an obstacle to reactant transport and a source of parasitic losses. The present work examines the behavior of two-phase flow in 500 μm × 500 μm × 60 cm channels with distributed water injection through a porous carbon paper wall to gain understanding of the physics of flows relevant to fuel cell water management challenges. Flow regime maps based on local gas and liquid flow rates are constructed for experimental conditions corresponding to current densities between 0.5 and 1 A/cm2 and stoichiometric coefficients from 1 to 4. Flow structures are analyzed along the entire length of the channel. It is observed that slug flow is favored to plug flow at high air flow rates and low liquid flow rates. Stratified flow dominates at high liquid flow rates. Along the axial flow direction, the flow regime consistently transitions from intermittent to wavy to stable stratified flow. This progression is quantified using a parameter of flow progression which characterizes the degree of development of the two-phase flow toward the stable stratified condition. This parameter is discussed in relation to fuel cell operating conditions. It provides a metric for analyzing liquid water removal mechanisms in the cathode channels of PEM fuel cells.


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