Investigation into the use of the electromagnetic flowmeter for two-phase flow measurements

Accurate prediction of the interfacial area concentration is essential to successful development of the interfacial transfer terms in the two-fluid model. Mechanistic modeling of the interfacial area concentration entirely relies on accurate local flow measurements over extensive flow conditions and channel geometries. From this point of view, accurate measurements of flow parameters such as void fraction, interfacial area concentration, gas velocity, bubble Sauter mean diameter, and bubble number density were performed by the image processing method at five axial locations in vertical upward bubbly flows using a 1.02 mm-diameter pipe. The frictional pressure loss was also measured by a differential pressure cell. In the experiment, the superficial liquid velocity and the void fraction ranged from 1.02 m/s to 4.89 m/s and from 0.980% to 24.6%, respectively. The obtained data give near complete information on the time-averaged local hydrodynamic parameters of two-phase flow. These data can be used for the development of reliable constitutive relations which reflect the true transfer mechanisms in two-phase flow. As the first step to understand the flow characteristics in mini-channels, the applicability of the existing drift-flux model, interfacial area correlation, and frictional pressure correlation was examined by the data obtained in the mini-channel.

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Annular two-phase flow measurements using phase Doppler anemometry with scattering angles of 30° and 70°

Flow Measurement and Instrumentation ◽

10.1016/0955-5986(95)93454-3 ◽

1995 ◽

Vol 6 (1) ◽

pp. 21-28 ◽

Cited By ~ 3

Author(s):

C.J. Bates ◽

R. Ayob

Keyword(s):

Two Phase Flow ◽

Phase Flow ◽

Two Phase ◽

Flow Measurements ◽

Phase Doppler Anemometry

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Study on Weight Function Distribution of Hybrid Gas-Liquid Two-Phase Flow Electromagnetic Flowmeter

Sensors ◽

10.3390/s20051431 ◽

2020 ◽

Vol 20 (5) ◽

pp. 1431 ◽

Cited By ~ 1

Author(s):

Yulin Jiang

Keyword(s):

Weight Function ◽

Green’S Function ◽

Green's Function ◽

General Model ◽

Measurement Errors ◽

Two Phase Flow ◽

Electromagnetic Flowmeter ◽

Phase Flow ◽

Two Phase ◽

Function Distribution

The electromagnetic flowmeter is usually used for single-phase fluid parameter measurement. When the measured fluid is gas-liquid two-phase flow, the geometry of the sensor measurement space will change with the movement of the gas, which will cause measurement errors. The weight function distribution is an important parameter to analyze such measurement errors. The traditional method for calculating the weight function of gas-liquid two-phase flow involves complex dimensional space transformation, which is difficult to understand and apply. This paper presents a new method for calculating the weight function of the gas-liquid two-phase flow electromagnetic flowmeter. Firstly, based on the measurement principle of the electromagnetic flowmeter, a general model of weight function of the gas-liquid two-phase flow electromagnetic flowmeter is built. Secondly, the bubbles in the fluid are regarded as the “isolated” points in the flow field. According to the physical connection between the “field” of the measured fluid and the “source” of the sensor electrode, the Green’s function expression based on gas-liquid two-phase flow is established. Then, combined with the boundary conditions of the measurement space of the electromagnetic flowmeter, the Green’s function is analyzed. Finally, the general model of weight function is solved by using the expression of Green’s function, then the expression of the weight function of the electromagnetic flowmeter is obtained when the measured fluid is hybrid gas-liquid two-phase flow. The simulation results show that the proposed method can reasonably describe the influence of the gas in the measured fluid on the output signal of the sensor, and the experimental results also indirectly prove the rationality of this method.

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