Maximum Two-Phase Flow Rates of Sub-Cooled Nitrogen Through a Sharp-Edged Orifice

1960 ◽  
pp. 299-306
Author(s):  
R. J. Simoneau
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

1997 ◽  
Vol 63 (612) ◽  
pp. 2707-2712
Author(s):  
Kiyoshi MINEMURA ◽  
Takeaki TAKEOKA ◽  
Shinji SHODA ◽  
Kazuyuki EGASHIRA ◽  
Yutaka OGAWA

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.


2020 ◽  
Vol 135 (8) ◽  
Author(s):  
Gabriela Rafałko ◽  
Romuald Mosdorf ◽  
Grzegorz Litak ◽  
Grzegorz Górski

AbstractMultiphase flow in a minichannel is a complex phenomenon which shows various patterns dynamics including slugs and bubbles depending on gas/fluid component flow rates. In this paper, air and water–glycerol mixed fluid flow has been studied. In the experiment, the volume flow rates of air and water–glycerol were changing. We studied transition of bubbles to slugs two-phase flow patterns by using multiscale entropy approach to digital camera signals and identified various patterns. The results clearly indicate that the multiscale entropy is an important complexity measure dependent on the flow distribution of the gas phase in a water–glycerol content.


2015 ◽  
Vol 52 (1) ◽  
pp. 18-32 ◽  
Author(s):  
T.S. Nguyen ◽  
A.D. Le

A mathematical model that couples the governing and constitutive equations of two-phase flow and mechanical equilibrium has been developed to simulate gas injection tests for both laboratory- and field-scale experiments. The model takes into consideration the inherent anisotropy of sedimentary rocks due to bedding by including an anisotropic elastoplastic model for the mechanical process and using an anisotropic permeability tensor for the flow processes for both water and gas. The gas and water flow rates are assumed to follow Darcy’s law. The relative permeability of each phase and their respective degrees of saturation are represented by the Van Genuchten’s functions. We simulated laboratory and field gas injection experiments in Opalinus clay, a candidate geological formation for the geological disposal of radioactive wastes. The numerical results show good agreement with the experimental data measured in these tests in terms of two-phase flow regimes and hydromechanical response at various monitoring locations. Damage zones, either pre-existing due to excavation or induced by high gas injection pressure, are shown to clearly influence the gas flow rates and directions and would need special consideration in the design and safety assessment of the repository system.


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