scholarly journals Data Analysis of Two-Phase Flow Simulation Experiment of Array Optical Fiber and Array Resistance Probe

Coatings ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1420
Author(s):  
Shuaifei Cui ◽  
Junfeng Liu ◽  
Kui Li ◽  
Qinze Li
Keyword(s):  
Optical Fiber ◽  
Flow Simulation ◽  
Phase Flow ◽  
Two Phase ◽  
Fiber Probe ◽  
Optical Fiber Probe ◽  
Optical Fiber Probes ◽  
Flow Through ◽  
Water Cut ◽  
Domestic Design

To solve the problem that traditional single-probe instruments cannot accurately measure the gas and water holdup, the domestic design of the array holdup measuring instrument Array of Optical and Resistance Tool (AORT), composed of five sets of optical fiber probes and five sets of resistance probes, is carried out in both gas–water and oil–water. Simulated measurement experiments were conducted under different water cut in phase flow. Through the analysis of the experimental data, the response relationship between the optical fiber probe and the resistance probe of the AORT instrument in different fluids was obtained. Then, the data under different conditions of fluid, flowrate and water cut in the experiment were compared by drawing. Interpolation algorithm was used to perform two-maintenance holdup imaging, and finally the holdup image was compared with the pictures of the flow in the pipe recorded during the experiment. The results show that the resistance probe has a better response under low water cut conditions, and the optical fiber probe has a better response under high gas cut conditions, which is consistent with the theoretical analysis. The imaging diagram and the flow pattern in the pipe during the experiment are in good agreement. It can be seen that the accuracy of the holdup measured by the AORT instrument under the test conditions is verified, and can provide technical support for further carrying out the measurement and interpretation of the holdup in future, as well as the improvement of the instrument and on-site testing.

Research on Measurement of Void Fraction for Vertically Rising Pipes by Optical Fiber Probe

2011 ◽  
Vol 361-363 ◽  
pp. 671-675 ◽  
Author(s):  
Feng Yun Chen ◽  
Wei Min Liu
Keyword(s):  
Optical Fiber ◽  
Void Fraction ◽  
Two Phase Flow ◽  
Exponential Model ◽  
Phase Flow ◽  
Two Phase ◽  
Cross Sectional ◽  
Fiber Probe ◽  
Optical Fiber Probe ◽  
Oil Gas

A way of measuring the average cross-sectional void fraction for vertically rising oil pipes by using closing valves quickly and optical fiber probe has been researched. Experiments were performed in oil-gas two-phase flow and the range of the average void fraction is 0.1～0.5. The relationship between average cross-sectional void fraction of a oil-gas two-phase flow and pipe’s center void fraction in vertically rising oil pipes, for different pipe diameters and varying oil flow, is obtained. An exponential model of average void fraction is also obtained with reference to Bankoff’s[1] variable density model. It is found that local void fraction reduces from center in radial direction and the local void fraction maximum value appears in the pipe’s center.

Numerical and Experimental Simulation of Two-Phase Tsunami Flow Through Buildings with Openings

2015 ◽  
Vol 09 (03) ◽  
pp. 1550007 ◽  
Author(s):  
Hartana ◽  
Keisuke Murakami
Keyword(s):  
Flow Simulation ◽  
Experimental Simulation ◽  
Phase Flow ◽  
Two Phase ◽  
Building Models ◽  
Flow Through ◽  
Heavy Loads ◽  
Complex Phenomena ◽  
Uplift Forces ◽  
Good Agreement

During tsunami action on a structure, the structure is subjected to heavy loads with complex phenomena which include the interactions among tsunami, structure and air. In order to mitigate tsunami damages on structures, it is important to understand the characteristics of tsunami hydraulic loads acting on the structures with taking into account the above interactions. In the present study, the characteristics of tsunami forces on a building structure are investigated using a two-phase flow model. Two types of building models, a building without openings and with openings, were dealt with; and the effects of openings on the building under the tsunami hydraulic loads are examined. The simulation results were compared with the results obtained from one-phase flow simulation, and also verified with experimental data. The numerical results show good agreement with the measured ones. Furthermore, the effects of air taken into the flow and opening configuration on the characteristics of pressures and uplift forces were also discussed.

A Newly Developed Technique for Detection of a Contact Position in Bubble Measurements by a Single-Tip Optical Fiber Probe

2011 ◽  
Author(s):  
Yuki Mizushima ◽  
Takayuki Saito
Keyword(s):  
Optical Fiber ◽  
Wedge Angle ◽  
Outer Edge ◽  
Chord Length ◽  
Two Phase ◽  
Frontal Surface ◽  
Fiber Probe ◽  
Optical Fiber Probe ◽  
Contact Position ◽  
The Relationship

An optical fiber probe has been frequently employed to measure bubble diameters, velocities, and local void fractions simultaneously in gas-liquid two-phase systems. For the application of the probe to tiny-bubble measurement, one of the authors already developed a Single-Tip Optical fiber Probe (STOP). The purpose of this study is to rapidly improve the measurement accuracy of the S-TOP. A bubble chord length pierced by the S-TOP is obtained. Consequently, the chord length depends on the pierced position. The chord lengths measured by the S-TOP include an error owing to the random positions pierced by the S-TOP; i.e. the measured chord length becomes shorter than the bubble minor axis, with a shift of the contact position towards the outer edge of the bubble. The S-TOP axis crosses the direction of the bubble motion at a random angle. This also causes a miscalculation of the chord lengths. In order to correct these errors in the S-TOP measurement, we need to detect the contact position and the intersection angles. To realize this, using a pre-signal is quite effective. The pre-signal is generated clearly and intensively, only when the S-TOP sensing tip is ground in a wedge shape and the tip touches vertically the center region of the bubble frontal surface. The pre-signal becomes weak and indistinct under the other contact conditions. Making the smart use of these phenomena, we are able to solve the above defects of the S-TOP. First, the relationship between the intensity of the pre-signal and the pierced positions/angles is systematically quantified. Second, a signal processing to detect the pierced positions/angles, based on the relationship, is established. Third, we discuss a mechanism of the pre-signal. We determine the most suitable S-TOP size, tip diameter and wedge-angle, for the most accurate measurement. Finally, we demonstrate the effectiveness of our newly proposed method.

Dielectric Stack Filters for Ex Situ and In Situ UV Optical-Fiber Probe Raman Spectroscopic Measurements

1997 ◽  
Vol 51 (11) ◽  
pp. 1722-1729 ◽  
Author(s):  
Calum H. Munro ◽  
Vasil Pajceni ◽  
Sanford A. Asher
Keyword(s):  
Raman Scattering ◽  
Optical Fiber ◽  
Raman Spectra ◽  
High Throughput ◽  
Single Stage ◽  
Fiber Probe ◽  
Optical Fiber Probe ◽  
Optical Fiber Probes ◽  
Uv Raman

Dielectric stack interference filters can be used in conjunction with a high-throughput single-stage spectrograph to facilitate the measurement of high signal-to-noise (S/N) ultraviolet (UV) Raman spectra with 228.9-nm and 244-nm excitation wavelengths. Placed between the sample and the spectrograph, these filters reflect Rayleigh scattering while transmitting Stokes-shifted Raman scattering. We have measured UV Raman bands from solid, highly scattering samples down to a 290-cm−1 shift from the Rayleigh line. The high throughput of the filtered single-stage spectrograph enables the measurement of UV Raman spectra from photo-labile samples, including DNA and the energetic materials pentaerythritol tetranitrate (PETN) and trinitrotoluene (TNT), with sufficiently low excitation powers and short accumulation times to minimize photo-alteration. High S/N UV preresonance and resonance Raman are obtained for PETN and TNT within 1 s, indicating the possible application of UV Raman spectroscopy as a rapid, highly selective screening methodology for the detection of trace levels of contraband explosives. Furthermore, the incorporation of these dielectric filters within a UV optical-fiber Raman probe head provides simultaneous Rayleigh rejection and removal of background silica Raman scattering. With the use of a 244-nm UV optical-fiber probe, we measured Raman spectra from 100 nM to 10 μM concentrations of polycyclic aromatic hydrocarbon (PAH) in water, even in the presence of an equimolar concentration of the visible fluorophore rhodamine 6G (R6G). Thus, we demonstrate the potential of UV Raman optical-fiber probes for minimally invasive in situ real-time monitoring at low analyte concentrations and within environments in which fluorescence backgrounds would prevent measurements with visible Raman optical-fiber probes.

Measurement of the Dynamical Mass Transfer of a Single CO2 Bubble Using LIF/HPTS Visualization and a Photoelectric Optical Fiber Probe

2010 ◽  
Author(s):  
Kodai Hanyu ◽  
Takayuki Saito
Keyword(s):  
Mass Transfer ◽  
Optical Fiber ◽  
Co2 Concentration ◽  
Measurement Methods ◽  
Two Phase Flows ◽  
Two Phase ◽  
Dynamical Mass ◽  
Fiber Probe ◽  
Optical Fiber Probe ◽  
Surrounding Liquid

Gas-liquid two-phase flows are widely encountered in industrial plants such as chemical reactors, power plants, environmental plants and so on. It is essential to clarify the dissolution process of the bubbles and the structure of the gas-liquid two-phase flows for realizing the efficient operation of these industrial reactors. However, it is very difficult to clarify them because of their complexity. We made a challenge of clarifying them in detail. First, we discuss the dynamical processes of the mass transfer from a zigzagging CO2 bubble of 2.9 mm in equivalent diameter by using three measurement methods (i.e. LIF (laser induced fluorescence)/HPTS (8-hydroxypyrene-1, 3, 6-trislfonic acid), PIV and a newly developed photoelectric optical fiber probe: POFP) effectively and mutually-complementarily. We directly visualized the dynamical mass transfer process from a zigzagging CO2 bubble to the surrounding liquid by using LIF/HPTS. We measured the surrounding liquid motion induced by the bubble buoyancy using PIV. We visualized a high-CO2-concentration thin layer around the bubble was transported to the bubble rear and accumulated into the horseshoe-like vortices. The clear horse-shoe-like vortices were observed just after the launch of the bubble from a needle. Then, the wreckage of the bubble wake was transported widely into the surrounding liquid by the buoyancy driven flows. We measured directly the CO2 concentration profile inside the bubble wake by using POFP. We succeeded in clarifying the profile of the CO2 concentration inside the bubble wake, which is difficult to obtain from only the LIF/HPTS method. From this result, we obtained that the CO2 concentration takes the maximum at the center region of the bubble wake and sharply decreases toward the outer edge of the bubble wake. Second, we simultaneously measured the diameters and velocities of the bubble by using POFP. We confirmed the performance of the POFP; the results via POFP were compared with those obtained from the visualization of the bubbles by using a high-speed video camera. We demonstrated mutually-complementary use of three measurement methods is very effective to experimentally understand the dynamical processes of the mass transfer from a zigzagging CO2 bubble to the surrounding liquid.

scholarly journals Influence of Bubble Deformation on the Signal Characteristics Generated Using an Optical Fiber Gas–Liquid Two-Phase Flow Sensor

Sensors ◽  
2021 ◽  
Vol 21 (21) ◽  
pp. 7338
Author(s):  
Yu Ma ◽  
Yangrui Zhang ◽  
Song Li ◽  
Weimin Sun ◽  
Elfed Lewis
Keyword(s):  
Optical Fiber ◽  
Chemical Engineering ◽  
Two Phase Flow ◽  
Three Dimensional ◽  
Phase Flow ◽  
Two Phase ◽  
Flow Measurements ◽  
Fiber Probe ◽  
Bubble Deformation ◽  
Wide Range

The use of optical fiber probe in two-phase flow measurements is very frequently encountered, especially in the applications of chemical engineering and petroleum industries. In this work, the influence of bubble piercing signals caused by bubble deformation is studied experimentally using a laboratory-prepared wedge-shaped fiber probe in a lab-scale gas–liquid flow generator. A three-dimensional simulation model is established to study the influence of bubble deformation on the piercing signals. A theoretical analysis of the characteristics of the pre-signal influenced by the bubble deformations is undertaken for a wide range of different modeled bubble shapes. Combining the experimental and simulation results, a promising analytical method to estimate the bubble shapes by analyzing the characteristics of pre-signals is proposed. The results of this investigation demonstrate that it is possible to estimate the bubble shapes before the fiber probe contacts the bubble surface. The method developed in this investigation is therefore highly promising for reducing errors caused by deformation during the probe piercing process.

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