Two-Phase Flow Measurement Techniques

Bertola, Volfango

doi:10.1007/978-3-7091-2538-0_6

Cited by 11 publications

(3 citation statements)

References 72 publications

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“…LDV [34,35] is another widely used optical method for the velocity measurement in two-phase flow, especially for the bubbly flow. It has a high frequency response and a wide measurement range [36], but LDV can only achieve single-point measurements. With the development of digital imaging technology, PIV/PTV [37][38][39] are being developed to measure the velocity of fluid.…”

Section: Introductionmentioning

confidence: 99%

Liquid flow measurement using phase isolation and an imaging method in horizontal gas–liquid two-phase flow

Niu

Wang

Wei

et al. 2020

Meas. Sci. Technol.

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A new imaging method based on phase isolation for the liquid flow measurement of gas-liquid two-phase flow is proposed in this study. A swirler is arranged upstream to isolate two-phase fluids. As the two-phase mixture passes through it, a strong swirl flow is generated. The gas is concentrated into the center of the tube and forms a gas core while the liquid phase is pushed to the tube wall and forms a uniform liquid film, which is where the swirl core-annular flow occurs. After phase isolation, many microbubbles, which are small enough to neglect their body force, appear in the liquid film. These phase-isolation-induced microbubbles are used as tracers to represent the local velocity of the liquid flow. A CCD camera is employed to track the motion of the bubbles at the focal plane and determines the velocity at this position. Then this measured local velocity is converted to the mean velocity of the liquid film by a velocity coefficient based on the similitude principle of the velocity profile. After the flow area of the liquid film is derived from the void fraction measurement by another CCD camera, the flowrate of liquid film is determined. The velocity coefficients which express the relation between local velocity and mean velocity of liquid film are obtained by a calibration experiment. Two conventional industry CCD cameras and corresponding individual LED illuminations constitute the imaging system. The image-processing algorithm was developed using the MATLAB image toolbox. A Air and tap water are used and their superficial velocity are in the range of 3.41 m s −1 ∼ 45.15 m s −1 and 0.022 m s −1 ∼ 0.265 m s −1 , respectively. The thickness of liquid film ranges from 72.75 µm to 423.11 µm and the diameter of microbubbles ranges from 11 µm to 35 µm.

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Section: Introductionmentioning

confidence: 99%

Liquid flow measurement using phase isolation and an imaging method in horizontal gas–liquid two-phase flow

Niu

Wang

Wei

et al. 2020

Meas. Sci. Technol.

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“…Each technique is sensitive to some physical property which is different for the two phases, such as the fluid density or the electrical conductivity and permittivity [3]- [5]. An indirect way to measure void fraction is through liquid height measurement and it has been reported as a good approximation of the void fraction of the cross-sectional area at certain experimental conditions and their operability [6]- [8].…”

Section: Introductionmentioning

confidence: 99%

Sensing Platform for Two-Phase Flow Studies

et al. 2019

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This paper describes the development and application of a sensing platform which consists of fast conductance sensors and proper data acquisition and management software which aims at the investigation of two-phase flow parameters in pipelines. A number of sensing nodes are connected through a network which allows monitoring the flow at different pipeline positions. In addition, a data management Web-based platform is presented in order to store and manage the massive volume of data generated by data acquisition. The sensor electronics has been evaluated in temporal response and the capability to measure the parameters such as void fraction time series and structure velocities. The preliminary study of horizontal two-phase flow experiment is presented showing the capability of the developed platform to monitor flow parameters along a pipe. INDEX TERMS Liquid height measurement, sensing platform, two-phase flow, two-wire sensor.

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“…This can be accomplished with phase separation methods [10], but for larger bubbles or stratified flow PIV cannot be applied due to the optical disturbances and reflections by the bubbles [11]. For laser Doppler velocimetry (LDV) air bubbles can serve as tracer particles, but the technique is limited to dispersed flows with a low concentration of bubbles [12]. A further requirement in this case is that the bubbles are following the liquid phase without slip.…”

Section: Introductionmentioning

confidence: 99%

On the influence of gas–liquid two-phase flow on Lorentz force velocimetry

Wiederhold¹,

Resagk²,

Cierpka³

2018

Meas. Sci. Technol.

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Lorentz force velocimetry (LFV) is a contactless and non-invasive flow measurement technique for electrical conducting fluids. When the fluid passes a magnetic field, a Lorentz force will be generated. The force is proportional to the electrical conductivity, to the velocity of the fluid, and to the square of the magnetic flux density. It is possible to apply this technique over a range of conductivities varying from high values as for liquid metals to lower values as typically for electrolytes (e.g. salt water). The main challenge is measuring the force, which is six orders of magnitude smaller for electrolytes in comparison to liquid metals. It was shown that LFV is insensitive to the shape of different velocity profiles and especially to strongly asymmetric profiles as long as the volume flow is constant. However, the influence of a second gaseous phase on the force signal remains an open question. This is of fundamental interest especially for chemical and food processing industries. To examine this influence in detail, electrolyte flow with different volume flow fractions was investigated for the current study. By using frits, it is possible to generate a homogeneous distribution of the second (gaseous) phase in the electrolyte. Small electrolyte velocities or flow rates (v < 1.5 m s −1 , Vl = 225 l min −1 ) enable the formation of slug flow and stratified wavy flow, and higher velocities (v > 1.8 m s −1 , Vl = 270 l min −1 ) the formation of bubbly two-phase flow in the used test section. By this means, it is possible to study a wide range of flow patterns in a horizontal duct. The experimental results are in good agreement with the analytical estimations for fully dispersed flow. However, for a nonhomogeneous distribution of air the force signal deviates much stronger. An explanation can be the superposition of Lorentz forces and magnetic forces, caused by differences of the magnetic susceptibilities of water and air, which will be discussed in greater detail.

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Two-Phase Flow Measurement Techniques

Cited by 11 publications

References 72 publications

Liquid flow measurement using phase isolation and an imaging method in horizontal gas–liquid two-phase flow

Liquid flow measurement using phase isolation and an imaging method in horizontal gas–liquid two-phase flow

Sensing Platform for Two-Phase Flow Studies

On the influence of gas–liquid two-phase flow on Lorentz force velocimetry

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