Gas Volume Fraction Measurement of Oil–Gas–Water Three-Phase Flows in Vertical Pipe by Combining Ultrasonic Sensor and Deep Attention Network

2021 ◽  
Vol 70 ◽  
pp. 1-9
Author(s):  
Weikai Ren ◽  
Ningde Jin ◽  
Lei OuYang ◽  
Lusheng Zhai ◽  
Yingyu Ren
Processes ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 760
Author(s):  
Guangtai Shi ◽  
Sijia Tao ◽  
Xiaobing Liu ◽  
Haigang Wen ◽  
Zekui Shu

The axial flow screw-type oil-gas multiphase pump is mainly applied to oil and gas transport in the deep sea. In the process of transporting the multiphase medium, the gas volume fraction (GVF) on the gas phase changes from time-to-time, resulting in the performance of the oil-gas multiphase pump being greatly influenced by the gas phase. This paper presents a detailed analysis of the gas-phase distribution law and the vortex distribution in the flow passages within the oil-gas multiphase pump by means of numerical calculations, supplemented by experimental verification. The results show that the gas phase is mainly concentrated in the diffuser at different GVFs, and the gas phase gathering in the diffuser becomes more significant with the increase in the GVF. The gas-phase volume fraction increases gradually from rim to hub, that is, the gas-phase gathering degree increases. The maximum gas-phase volume distribution area is mainly concentrated in the area near the hub of the diffuser inlet and the middle blade height area at the outlet of the diffuser. The flow in the impeller is relatively stable under the different GVFs, while there is a large vortex near the inlet of the diffuser near the hub, and there is a backflow phenomenon between the outlet of the diffuser and the tip clearance of the impeller. The volume fraction of the gas phase near the rim fluctuates more than that near the hub because the gas phase is squeezed by the liquid phase more violently. The research results can provide theoretical guidance for the optimal design of oil-gas multiphase pump blades.


2012 ◽  
Vol 152-154 ◽  
pp. 1221-1226
Author(s):  
H.A.M. Hasan Abbas

Multiphase flows, where two or even three fluids flow simultaneously in a pipe are becoming increasingly important in industry. In order to measure the flow rate of gas-water two phase flows accurately, the void fraction (gas volume fraction) in two phase flows must be precisely measured. The differential pressure technique has proven attractive in the measurement of volume fraction. This paper presents the theoretical and experimental study of the void fraction measurement in bubbly gas water two phase flows using differential pressure technique (the flow density meter).


Sensors ◽  
2020 ◽  
Vol 20 (2) ◽  
pp. 481
Author(s):  
Weikai Ren ◽  
An Zhao ◽  
Ningde Jin

The complex flow structure and interfacial effect in oil–gas–water three-phase flow have made the void fraction measurement a challenging problem. This paper reports on the void fraction measurement of oil–gas–water three-phase flow using a mutually perpendicular ultrasonic sensor (MPUS). Two pairs of ultrasonic probes are installed on the same pipe section to measure the void fraction. With the aid of the finite element method, we first optimize the emission frequency and geometry parameters of MPUS through examining its sensitivity field distribution. Afterward, the oil–gas–water three-phase flow experiment was carried out in a vertical upward pipe with a diameter of 20 mm to investigate the responses of MPUS. Then, the void fraction prediction models associated with flow patterns (bubble flow, slug flow, and churn flow) were established. Compared to the quick closing valves, MPUS obtained a favorable accuracy for void fraction measurement with absolute average percentage error equaling 8.983%, which indicates that MPUS can satisfactorily measure the void fraction of oil–gas–water three-phase flow.


2020 ◽  
Vol 10 (1) ◽  
pp. 345
Author(s):  
Wei Han ◽  
Xing Li ◽  
Youliang Su ◽  
Min Su ◽  
Rennian Li ◽  
...  

With the decrease of oil and gas resources on land, increased attention has been paid to multiphase oil–gas exploitation and the transportation technology represented by oil–gas multiphase pumps. The helical–axial multiphase pump has become the focus of research on oil and gas mixed transmission technology due to its relatively high operating efficiency and adaptability to a wide range of gas volume fraction changes. In order to investigate the thickness variation in the air foil from the hub to the shroud of the blade on the mixture transportation characteristics of the gas–liquid two-phase flow in a helical–axial pump, the thickness ratio coefficient ξ was introduced, and the hydraulic performance of the single compression unit with different thickness ratio coefficients was investigated. A single compression unit including an impeller, diffuser, inlet section and outlet section of a helical–axial multiphase pump. The hydraulic performance including the hydraulic head and efficiency was investigated by numerical simulation with the Eulerian multiphase model and the shear stress transport (SST) k-w turbulence model. In order to demonstrate the validity of the numerical simulation approach, the hydraulic head and efficiency of the basic model was measured based on a gas–liquid two-phase flow pump performance test bench. The simulation results agreed well with the experimental results; the error between the simulation results and experimental results of different inlet gas volume fractions was within 10% at the design point, which indicated the numerical simulation method can be used in the research. The thickness ratio coefficient ξ, which was taken as a variable, and the aggregation degree λ of the gas were introduced to analyze the gas–liquid mixture transportation characteristics of the pump. The thickness ratio coefficient was selected in a range from 0.8 to 1.8. The results showed that, for the same hub thickness, the head coefficient and efficiency increase, and the aggregation degree of gas decreases with the decreasing of the thickness ratio coefficient. The head coefficient of the modification multiphase pump was 5.8% higher in comparison to the base pump while the efficiency was 3.1% higher than that of the base pump, the aggregation degree of this model was the lowest, which was 30.3%; the optimal model in the research was the model of scheme 1 with ξ = 0.8. The accumulation of gas in the flow passage of the impeller could be delayed to the trailing edge of the blade by adjusting the thickness ratio coefficient, which produced a super-separated airfoil for helical–axial multiphase pumps and effectively ensured reliable operation under high gas volume fraction conditions. The accumulation area of gas was consistent with the area in which the gradient of turbulent kinetic energy was large.


Processes ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 650
Author(s):  
Guangtai Shi ◽  
Dandan Yan ◽  
Xiaobing Liu ◽  
Yexiang Xiao ◽  
Zekui Shu

The gas volume fraction (GVF) often changes from time to time in a multiphase pump, causing the power capability of the pump to be increasingly affected. In the purpose of revealing the pressure load characteristics of the multiphase pump impeller blade with the gas-liquid two-phase case, firstly, a numerical simulation which uses the SST k-ω turbulence model is verified with an experiment. Then, the computational fluid dynamics (CFD) software is employed to investigate the variation characteristics of static pressure and pressure load of the multiphase pump impeller blade under the diverse inlet gas volume fractions (IGVFs) and flow rates. The results show that the effect of IGVF on the head and hydraulic efficiency at a small flow rate is obviously less than that at design and large flow rates. The static pressure on the blade pressure side (PS) is scarcely affected by the IGVF. However, the IGVF has an evident effect on the static pressure on the impeller blade suction side (SS). Moreover, the pump power capability is descended by degrees as the IGVF increases, and it is also descended with the increase of the flow rate at the impeller inlet. Simultaneously, under the same IGVF, with the increase of the flow rate, the peak value of the pressure load begins to gradually move toward the outlet and its value from hub to shroud is increased. The research results have important theoretical significance for improving the power capability of the multiphase pump impeller.


2014 ◽  
Vol 136 (7) ◽  
Author(s):  
Sowmitra Singh ◽  
Tiffany Fourmeau ◽  
Jin-Keun Choi ◽  
Georges L. Chahine

This paper addresses the concept of thrust augmentation through bubble injection into an expanding-contracting nozzle with a throat. The presence of a throat in an expanding-contracting nozzle can result in flow transition from the subsonic regime to the supersonic regime (choked conditions) for a bubbly mixture flow, which may result in a substantial increase in jet thrust. This increase would primarily arise from the fact that the injected gas bubbles expand drastically in the supersonic region of the flow. In the current work, an analytical 1D model is developed to capture choked bubbly flow in an expanding-contracting nozzle with a throat. The study provides analytical and numerical support to analytical observations and serves as a design tool for nozzle geometries that can achieve efficient choked bubbly flows through nozzles. Starting from the 1D mixture continuity and momentum equations, along with an equation of state for the bubbly mixture, expressions for mixture velocity and gas volume fraction were derived. Starting with a fixed geometry and an imposed upstream pressure for a choked flow in the nozzle, the derived expressions were iteratively solved to obtain the exit pressures and velocities for different injected gas volume fractions. The variation of thrust enhancement with the injected gas volume fraction was also studied. Additionally, the geometric parameters were varied (area of the exit, area of the throat) to understand the influence of the nozzle geometry on the thrust enhancement and on the flow conditions at the inlet. This parametric study provides a performance map that can be used to design a bubble augmented waterjet propulsor, which can achieve and exploit supersonic flow. It was found that the optimum geometry for choked flows, unlike the optimum geometry under purely subsonic flows, had a dependence on the injected gas volume fraction. Furthermore, for the same injected gas volume fraction the optimum geometry for choked flows resulted in greater thrust enhancement compared to the optimum geometry for purely subsonic flows.


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