Measurement of a Void Fraction in Bubbly Gas-Water Two Phase Flows Using Differential Pressure Technique

2012 ◽  
Vol 152-154 ◽  
pp. 1221-1226
Author(s):  
H.A.M. Hasan Abbas
Keyword(s):  
Experimental Study ◽  
Void Fraction ◽  
Volume Fraction ◽  
Differential Pressure ◽  
Flow Density ◽  
Two Phase Flows ◽  
Two Phase ◽  
Gas Volume Fraction ◽  
Fraction Measurement ◽  
Gas Volume

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).

Visual Criteria for Measuring Two-phase Flow Rate in Venturi with Flow Homogenizer

2015 ◽  
Vol 137 (8) ◽  
Author(s):  
Sangho Sohn ◽  
Jaebum Park ◽  
Dong-Wook Oh
Keyword(s):  
Flow Rate ◽  
High Speed ◽  
Two Phase Flow ◽  
Volume Fraction ◽  
Differential Pressure ◽  
Phase Flow ◽  
Two Phase ◽  
3 Dimensional ◽  
Lower Amplitude ◽  
Gas Volume

A simple use of Venturi might be used to measure two-phase flow rate within relatively low GVF(gas volume fraction). Upstream flow entering Venturi can be improved with installed flow homogenizer which is easily fabricated by 3-dimensional printer with multiple holes. Simultaneous measurement between high-speed flow visualization and dynamic differential pressure measurement was made to find visual criteria for two-phase flow rate measurement with different GVF ranged from 0% to 30%. It was observed that the two-phase flow rate can be reliably measured up to 15% of GVF using flow homogenizer. FFT(Fast-Fourier Transform) results proved that the long flow homogenizers (type 2 and 4) showed a lower amplitude of differential pressure (Δp) than the short flow homogenizers (type 1 and 3) respectively. So the optimized flow homogenizer can be useful to measure two-phase flow rate at low GVF.

Experimental study on a new gas–liquid separator for a wide range of gas volume fraction

2020 ◽  
Vol 160 ◽  
pp. 561-570 ◽  
Author(s):  
Xiaobo Zeng ◽  
Guangming Fan ◽  
Junxiu Xu ◽  
Antai Liu ◽  
Yifan Xu ◽  
...  
Keyword(s):  
Experimental Study ◽  
Volume Fraction ◽  
Wide Range ◽  
Gas Volume Fraction ◽  
Gas Volume ◽  
Liquid Separator

scholarly journals Precise Void Fraction Measurement in Two-phase Flows Independent of the Flow Regime Using Gamma-ray Attenuation

2016 ◽  
Vol 48 (1) ◽  
pp. 64-71 ◽  
Author(s):  
E. Nazemi ◽  
S.A.H. Feghhi ◽  
G.H. Roshani ◽  
R. Gholipour Peyvandi ◽  
S. Setayeshi
Keyword(s):  
Flow Regime ◽  
Void Fraction ◽  
Gamma Ray ◽  
Two Phase Flows ◽  
Two Phase ◽  
Gamma Ray Attenuation ◽  
Fraction Measurement

scholarly journals Effect of Gas Volume Fraction on the Energy Loss Characteristics of Multiphase Pumps at Each Cavitation Stage

Water ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2293
Author(s):  
Jianwei Shi ◽  
Sijia Tao ◽  
Guangtai Shi ◽  
Wenwu Song
Keyword(s):  
Energy Loss ◽  
Volume Fraction ◽  
Axial Flow ◽  
Two Phase ◽  
Multiphase Pump ◽  
Cavitation Phenomenon ◽  
Flow Loss ◽  
Gas Volume Fraction ◽  
Critical Cavitation ◽  
Gas Volume

In the process of conveying a medium, when the inlet pressure is low, the cavitation phenomenon easily occurs in the pump, especially in the gas–liquid two-phase working condition. The occurrence of the cavitation phenomenon has a great impact on the performance of the multiphase pump. In this paper, the SST (sheard stress transport) k-ω turbulence model and ZGB (Zwart–Gerber–Belamri) cavitation model were used to simulate the helical axial flow multiphase pump (hereinafter referred to as the multiphase pump), and the experimental verification was carried out. The effect of gas volume fraction (GVF) on the energy loss characteristics in each cavitation stage of the multiphase pump is analyzed in detail. The study shows that the critical cavitation coefficient of the multiphase pump gradually decreases with the increase in GVF, which depresses the evolution of cavitation, and the cavitation performance of the multiphase hump is improved. The ratio of total loss and friction loss to total flow loss in the impeller fluid domain gradually increases with the development of cavitation, and the pressurization performance of the multiphase pump gradually decreases with the development of cavitation. The results of the study can provide theoretical guidance for the improvement of the performance of the multiphase pump.

Numerical Study of Reactor Cooling Pumps Under Two-Phase Gas-Liquid Flow

2014 ◽  
Author(s):  
Peng Wang ◽  
Shouqi Yuan ◽  
Xiuli Wang ◽  
Guidong Li ◽  
Banglun Zhou ◽  
...  
Keyword(s):  
Computational Models ◽  
Volume Fraction ◽  
Numerical Study ◽  
Linear Increase ◽  
Suction Surface ◽  
Two Phase ◽  
Gas Volume Fraction ◽  
Head Pressure ◽  
Simulation Results ◽  
Gas Volume

In this paper, the unsteady pressure field and head-drop phenomenon caused by one of the most dangerous accidents in reactor plants known as Loss of Coolant Accident (LOCA) in its worse condition called small LOCA have been investigated numerically by computational fluid dynamics (CFD) in a nuclear reactor cooling pump. Five computational models with different blades had been calculated using Eulerian-Eulerian two fluid models using a multiphase approach. Simulation results show increasing gas volume fraction results in a sharp decline of the head pressure and pump efficiencies for each of 5 kinds of pumps modeled. This is especially evident for both the head pressure of impeller types C and impeller E. Here only have operating at half (58m and 54.9m)of the design condition when the gas volume fraction is 25%. The analysis of inner flow field of the five model pumps shown that the lower pressure area appeared at the inlet and outlet of the impeller as well as a small part distribution at the inlet of the diffuser, which is the main reason made the gas bubbles tend to concentrate at the impeller eye on the suction surface, the distribution of two phases appeared by non-linear increase and random located in whole passages. The experimental and simulation results are compared and are in good agreement with values obtained for the global performance at lower gas contents (below20%). When the gas contents increases to 25%, the bubbles occupy the passages, which effectively causes unsteady flow in the gas phase cannot be neglected for accurately predicting the inner flow of the pump. These results imply that this numerical method is suitable for the two-phase flow under certain gas contents (below 20%) in the reactor cooling pump.

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