Automatic identification of flow regimes in vertical two-phase flow using differential pressure fluctuations

Abstract The fluctuating pressure drop for air-water two-phase flow was measured in the vertical upward section of U-type tube with 0.05m I.D. The feature of the fluctuations was extracted by means of statistical and chaotic theories. The influence of liquid superficial velocity on the features was also investigated. The results showed that the mean, root mean square, fractal dimension of pressure drop fluctuations is function of flow regimes. The fractal dimension can be larger than 1.5 in annular flow with great liquid superficial velocity which is reported for the first time. Furthermore, the present paper provided a feasible solution, which the gas-liquid two-phase flow regimes can be recognized automatically and objectively on basis of the combination of the Counter Propagation Network (CPN) and the FFT coefficients of the differential pressure fluctuations. The recognition possibility is determined by the clustering results of the Kohonen layer in the CPN. With the presented test cases, the possibility can be greater than 90 percent for different liquid phase velocity.

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Statistical characteristics of differential pressure fluctuations and flow patterns of gas-liquid two-phase flow in an inclined pipe.

TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series B ◽

10.1299/kikaib.54.854 ◽

1988 ◽

Vol 54 (500) ◽

pp. 854-858 ◽

Cited By ~ 1

Author(s):

Goichi MATSUl ◽

Toshihiko AIZAWA ◽

Toshio KUMAZAWA

Keyword(s):

Two Phase Flow ◽

Pressure Fluctuations ◽

Flow Patterns ◽

Differential Pressure ◽

Statistical Characteristics ◽

Phase Flow ◽

Two Phase ◽

Inclined Pipe

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Two-Phase Flow Induced Force Fluctuations on Pipe Bend

Volume 2B: Thermal Hydraulics ◽

10.1115/icone22-30573 ◽

2014 ◽

Cited By ~ 2

Author(s):

Shuichiro Miwa ◽

Yang Liu ◽

Takashi Hibiki ◽

Mamoru Ishii ◽

Yoshiyuki Kondo ◽

...

Keyword(s):

Flow Regime ◽

Slug Flow ◽

Two Phase Flow ◽

Pressure Fluctuations ◽

Flow Regimes ◽

Phase Flow ◽

Liquid Slug ◽

Two Phase ◽

Pipe Bend ◽

Force Fluctuation

In this study, fluctuating force induced by both upward and horizontal gas-liquid two-phase flow on 90 degree pipe bend at atmospheric condition was investigated. First, the database comprised of dynamic force signals and two-phase flow parameters such as volumetric fluxes, area averaged void fraction and pressure fluctuations covering entire two-phase flow regimes was developed for both flow orientations. Then, study was conducted to develop a model which is capable of predicting the force fluctuation frequency and magnitudes particularly for the slug flow regime. The model was fundamentally developed from the local instantaneous two-fluid model which was applied to the control volume around the elbow test section. Main contribution of the force fluctuation of two-phase flow is from the momentum and pressure fluctuations for most of the flow regimes. For slug flow regime, however, water-hammer like impact was produced by the collision of liquid slug against the structure surface. In order to consider that effect, the liquid slug impact force model was developed. The model utilizes two-group interfacial area concentration correlation to treat the flow regime transition without an abrupt discontinuity. It was found that the newly developed model is capable of predicting two-phase flow induced force fluctuation and dominant frequency range with satisfactory accuracy for flow regimes up to churn-turbulent.

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Measurement for Individual Gas-Liquid Two-Phase Flow Rates Based on Stochastic Features of Differential Pressure Fluctuation

Volume 2: Fora, Parts A and B ◽

10.1115/fedsm2007-37470 ◽

2007 ◽

Author(s):

Tomomi Uchiyama ◽

Hirokazu Tominaga ◽

Kiyoshi Minemura

Keyword(s):

Two Phase Flow ◽

Pressure Fluctuations ◽

Vortex Generator ◽

Measuring Method ◽

Differential Pressure ◽

Phase Flow ◽

Two Phase ◽

Flow Rates ◽

Individual Phase ◽

The Individual

This study proposes a measuring method for the individual phase flow rates of gas-liquid two-phase mixtures flowing through a pipe. First, the time-variations for pressure are measured at three points around a vortex generator mounted in the pipe under the known flow rates. Secondly, the stochastic features of the differential pressure fluctuations, such as the mean and the standard deviation, are calculated to construct a database relating the flow rates with the stochastic features. Consequently, if the differential pressure fluctuations are measured under unknown flow rates, the individual phase flow rates are successfully identified from the database. A neural network is employed for the identification. This study also applies the proposed method for the measurement of air-water two-phase flow and discusses the measured results.

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