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.

Study of Behavior of Two Phase Flow in Vertical Large Diameter Pipe

2010 ◽  
Author(s):  
Mohammad Hassan Kebriayi ◽  
Hadi Karrabi ◽  
Mohsen Rezasoltani ◽  
M. H. Saidi
Keyword(s):  
Void Fraction ◽  
Two Phase Flow ◽  
Flow Behavior ◽  
Large Diameter ◽  
Petroleum Industry ◽  
Phase Flow ◽  
Empirical Correlations ◽  
Two Phase Flows ◽  
Two Phase ◽  
Cross Sectional

Knowledge of Air-water two phase flows is significant to different engineering systems such as chemical reactors and power plant and petrochemical and petroleum industry. One of the most industrial cases of two phase flow is two phase flow in vertical large pipes. In this paper in order to find two phase flow behavior along vertical large diameter pipes we simulate air inlets with different number of holes and different hole diameters in the same flow rate of air. In addition, flow characteristics such as cross-sectional void fraction and velocity and pressure were considered. To achieve this aim, main equations of flow have been developed for investigation of flow behavior in air-water two phase flows. 3-D numerical analyses were performed by a designed and written CFD package which is based on volume of fluid (VOF) approach. Geometries, which have been studied in this article, are round tubes with diameter of 5 cm and with length of 1 and 5 m. The fluid is assumed to be viscous and incompressible. The pressure-velocity coupling is obtained using the SIMPLEC algorithm. The results showed that at the entrance of the pipe the effect of air inlet geometry is significant while at the whole pipe this effect suppressed. Furthermore increasing the velocity at the inlet can increase average void fraction and decrease pressure loses along the pipe axis. Numerical results were compared with available empirical correlations and this comparison shows good agreement between this work and empirical correlations.

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.

Development of a Multi-Dimensional Measurement Sensor of Void Fraction and Phasic Velocity for Boiling Two-Phase Flow in a 5×5 Heated Rod Bundle

2014 ◽  
Author(s):  
Takahiro Arai ◽  
Masahiro Furuya ◽  
Taizo Kanai ◽  
Kenetsu Shirakara ◽  
Yoshihisa Nishi
Keyword(s):  
Void Fraction ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Two Phase ◽  
Experimental Conditions ◽  
Cross Sectional ◽  
Rod Bundle ◽  
Cross Correlation Analysis ◽  
Flow Experiment ◽  
The Cross

A subchannel void sensor (SCVS) was developed to measure the cross-sectional distribution of a void fraction in a 5×5 heated rod bundle with o.d. 10 mm and heated length 2000 mm, and applied in a boiling two-phase flow experiment under the atmospheric conditions assumed in an accident and spent fuel pool. The SCVS comprises 6-wire by 6-wire and 5-rod by 5-rod electrodes. Wire electrodes 0.2 mm in diameter are arranged in latticed patterns between the rod bundle, while a conductance value in a region near one wire and another gives a local void fraction in the central-subchannel region. 32 points (= 6×6−4) of the local void fraction can be obtained as a cross-sectional distribution. In addition, a local void fraction near the rod surface can be estimated by a conductance value in a region near one wire and one rod using the simulated fuel rods as rod electrodes, which allows 100 additional points (=4×25) of the local void fraction to be acquired. The devised sensors are installed at five height levels to acquire two-phase flow dynamics in an axial direction. A pair of SCVS is mounted at each level and placed 30 mm apart to estimate the one-dimensional phasic velocity distribution based on the cross-correlation analysis of both layers. The time resolution of void measurement exceeds 800 frames (cross-sections) per second. The heated rod bundle has an axially and radially uniform power profile, and eight pairs of sheath thermocouples are embedded on the heated rod to monitor its surface temperature distribution. The boiling two-phase flow experiment, which simulated a boil-off process, was conducted with the devised SCVS and experimental data was acquired under various experimental conditions, such as inlet-flow velocity, rod-bundle power and inlet subcooling. The experimental results exhibited axial and radial distribution of two-phase flow structures, i.e. void-fraction and phasic-velocity distributions quantitatively.

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