scholarly journals PIV Measurement of Gas-liquid Two-phase Flow and Its Current Problems

2001 ◽  
Vol 21 (80) ◽  
pp. 2-7_1
Author(s):  
Fujio YAMAMOTO ◽  
Yuichi MURAI
Keyword(s):  
Two Phase Flow ◽  
Phase Flow ◽  
Two Phase ◽  
Piv Measurement

Interaction Between Two Falling Droplets in the Liquid-Liquid Two Phase Flow

2011 ◽  
Author(s):  
Nao Ninomiya ◽  
Takeshi Mori
Keyword(s):  
Aqueous Solution ◽  
Multiphase Flow ◽  
Physical Mechanism ◽  
Two Phase Flow ◽  
Refractive Indices ◽  
Phase Flow ◽  
Two Phase ◽  
Piv Measurement ◽  
The Difference ◽  
Simultaneous Visualization

Although the phenomena related to the multiphase flow can be found in many kinds of industrial and engineering applications, the physical mechanism of the multiphase flow has not been investigated in detail. The major reason for the lack of data in the multiphase flow lies in the difficulties in measuring the flow quantities of the multiple phases simultaneously. The difference in the refractive indices makes the visualization in the vicinity of the boundary of the multiple phases almost impossible. In this study, the refractive index of the aqueous phase has been equalized to that of the oil phase by adjusting the concentration of aqueous solution. Presently, the simultaneous visualization and the PIV measurement have been carried out about the both phases of the liquid-liquid two-phase flow. The measurement has been carried out for the flow field around and inside of two falling droplets interacting each other while they travel.

Fluorescent Particle Injection Technique for Two-Phase Flow Measurement Using Particle Image Velocimetry

2006 ◽  
Author(s):  
Steven P. O’Halloran ◽  
B. Terry Beck ◽  
Mohammad H. Hosni ◽  
Steven J. Eckels
Keyword(s):  
Particle Image Velocimetry ◽  
Particle Image ◽  
Two Phase Flow ◽  
Phase System ◽  
Phase Flow ◽  
Two Phase ◽  
Particle Injection ◽  
Piv Measurement ◽  
Image Velocimetry ◽  
Fluorescent Particles

Particle image velocimetry (PIV) is a well established measurement technique to measure velocity in a variety of different fluids. Using PIV to measure single-phase flow is well established, but recently PIV has been used to measure two-phase flows as well. Most two-phase PIV measurements have been for dispersed or bubbly flows, often utilizing the bubbles or droplets as PIV seed particles. However, there are other types of two-phase flow situations, such as stratified or slug flow, in which PIV measurement techniques are not yet well established. Situations such as these require both liquid and gas phases to be seeded separately with particles that can distinguish each phase. A particle injection method is presented for the air phase of a two-phase system using fluorescent tracer particles. Information about the system, including details of the fluorescent particles and injection device are given. The device injects micron sized fluorescent particles at a uniform rate into the flow of interest. A cut-off lens filter on the PIV camera is used to distinguish the fluorescent particles used for the air phase from non-fluorescent particles used in the liquid phase. Results using the technique with a two-phase air/water system in a thin rectangular channel for stratified/wavy flow are given. The channel is enclosed in a clear acrylic plastic tank and the dimensions of the channel are 600 mm long, 40 mm high, and 15 mm wide. The results demonstrate the ability to use PIV to measure the gas phase of a two-phase system for stratified/wavy flow and the method could be extended to other two-phase flow regimes as well.

scholarly journals PIV measurement of particle motion in spiral gas–solid two-phase flow

1999 ◽  
Vol 19 (4) ◽  
pp. 194-203 ◽  
Author(s):  
Kaoru Miyazaki ◽  
Gang Chen ◽  
Fujio Yamamoto ◽  
Jun-ichi Ohta ◽  
Yuichi Murai ◽  
...  
Keyword(s):  
Particle Motion ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Two Phase ◽  
Piv Measurement

Wavelet Spatial Energy Spectrums Studies on Drag Reduction by Microbubble Injection

2006 ◽  
Author(s):  
Ling Zhen ◽  
Yassin A. Hassan
Keyword(s):  
Energy Spectrum ◽  
Drag Reduction ◽  
Channel Flow ◽  
Two Phase Flow ◽  
Turbulent Channel Flow ◽  
Phase Flow ◽  
Two Phase ◽  
Wavelet Energy ◽  
Piv Measurement ◽  
Fluid Particles

In this study, continuous wavelet transforms and spatial correlation techniques are employed to determine the space-localized wavenumber energy spectrum of the velocity signals in turbulent channel flow. The flow conditions correspond to single phase flow and microbubbles injected two phase flow. The wavelet energy spectrums demonstrate that the wavenumber (eddy size) content of the velocity signals is not only space-dependent but also microbubbles can impact the eddy size content. Visual observations of the wavelet energy spectrum spatial distribution was realized by using Particle Image Velocimetry (PIV) measurement technique. The two phase flow condition corresponds to a drag reduction of 38.4% with void fraction of 4.9%. The present results provide evidence that microbubbles in the boundary layer of a turbulent channel flow can help adjust the eddy size distributions near the wall. This can assist in explaining that microbubbles are performing as buffers to keep the energy of fluid particles going in streamwise direction and reducing the energy of fluid particles going in normal direction.

scholarly journals Development of PIV measurement technique in turbulent flow laden with binary-size particle groups

2020 ◽  
Vol 37 ◽  
pp. 161-171
Author(s):  
Wei-Cheng Chen ◽  
Keh-Chin Chang
Keyword(s):  
Spatial Information ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Two Phase ◽  
Phase Discrimination ◽  
Piv Measurement ◽  
Mean Size ◽  
Field Measuring ◽  
The Mean ◽  
Binary Group

Abstract Particle image velocimetry (PIV) is an instantaneous whole-field measuring diagnostic that makes it feasible to measure the microscale spatial information of the interphase dynamics for good understanding of two-phase flow. However, application of PIV to the two-phase flow measurement is still a state of the art so far. A double-discriminating process in terms of gray level and size of image patterns together with the median mask technique is developed. The test flow is a turbulent air wake laden with a binary group of particles with the mean size of 2.7 μm (representing the carrier phase) and 55 μm (representing the dispersed phase). It is demonstrated that the velocity measurements of both phases can be successfully performed through the combined PIV/PTV (particle tracking velocimetry) scheme associated with the developed phase discrimination method. It is noted that the discriminating capability of the size ratio between the large- and small-particle groups in the study is around 20 together with the mean size of O(100 μm) for small particles, which is the commonly required size for the seedings used in the PIV measurements of airflows, as compared to the size of O(101  μm) adopted in the current two-phase PIV measurement methods.

PIV Measurement of Carbon Dioxide Gas-Liquid Two-Phase Nozzle Flow

2015 ◽  
Author(s):  
Satoshi Ueno ◽  
Wakana Tsuru ◽  
Yoichi Kinoue ◽  
Norimasa Shiomi ◽  
Toshiaki Setoguchi
Keyword(s):  
Carbon Dioxide ◽  
High Speed ◽  
Two Phase Flow ◽  
Nozzle Flow ◽  
Phase Flow ◽  
Two Phase ◽  
Flow Acceleration ◽  
Carbon Dioxide Gas ◽  
Piv Measurement ◽  
Carbon Dioxide Co2

As a refrigerant used for a refrigeration cycle, carbon dioxide (CO2) is regarded. In the case that CO2 is used as a refrigerant, a gas-liquid two-phase flow ejector is very important. The gas-liquid two-phase flow ejector consists of a driving flow nozzle, a suction chamber, a mixing section and a diffuser. It is important for optimally designing the driving flow nozzle of the two-phase flow ejector to make clear the acceleration characteristics of the high speed gas-liquid two-phase flow. However, there is only a few study examples to evaluate the acceleration performance reasonably. Therefore, the purpose of this study is to measure the acceleration characteristics and temperature distribution in the CO2 gas-liquid two-phase flow nozzle of the CO2 two-phase flow ejector by experiment. In the experiment, CO2 is blown down through the convergent-divergent nozzle and is discharged into the atmosphere. Visualization of the nozzle flow has been carried out by Particle Image Velocimetry (PIV). Temperature measurement has been carried out by thermocouples. Obtained velocity distribution of gas-liquid two-phase flow nozzle have been considered as the droplets velocity. By the experiment, these velocity distributions in parts of the nozzle and these temperature distributions in the nozzle are obtained. Therefore, the flow acceleration in the nozzle divergent part is clarified by the experimental work.

A multiphase, micro-scale PIV measurement technique for liquid film velocity measurements in annular two-phase flow

2015 ◽  
Vol 68 ◽  
pp. 27-39 ◽  
Author(s):  
A.C. Ashwood ◽  
S.J. Vanden Hogen ◽  
M.A. Rodarte ◽  
C.R. Kopplin ◽  
D.J. Rodríguez ◽  
...  
Keyword(s):  
Liquid Film ◽  
Measurement Technique ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Velocity Measurements ◽  
Two Phase ◽  
Micro Scale ◽  
Piv Measurement
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