An application of the wavelet analysis technique for the objective discrimination of two-phase flow patterns

Nguyen, Van Thai; Euh, Dong-Jin; Song, Chul-Hwa

doi:10.1016/j.ijmultiphaseflow.2010.04.007

Cited by 66 publications

(17 citation statements)

References 27 publications

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“…A wavelet based approach was used by [12] for two-phase flow pattern characterization by using the void fraction signals obtained from a multi-channel Impedance Void Meter (IVM). Furthermore Elperin and Klochko [13] applied a wavelet transform-based approach to wall pressure fluctuations to identify two-phase flow patterns in vertical pipes for implementation in an on-line flow regime identification system.…”

Section: Introductionmentioning

confidence: 99%

Monitoring Cavitation Regime From Pressure and Optical Sensors: Comparing Methods Using Wavelet Decomposition for Signal Processing

2015

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A cavitating two-phase flow of water in a pipe with area shrinkage was experimentally investigated, acquiring at high sampling rate pressure signals and images of the cavitating flow-field. The fluctuations of the pressure measurements in the internal orifice and of the intensity level of the images' pixels were decomposed using the wavelet transform to analyze the frequency distribution of the signals energy with respect to the flow behavior and to highlight the influence of temperature on the phenomena under investigation. It was shown that the energy content at each frequency band of the acquired signals is well related to cavitation flow-field behavior.

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Section: Introductionmentioning

confidence: 99%

Monitoring Cavitation Regime From Pressure and Optical Sensors: Comparing Methods Using Wavelet Decomposition for Signal Processing

2015

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“…The local measurements of the void fraction, bubble diameter, and liquid velocity using the five-sensor conductivity probe [25] and the bi-directional flow tube [26] were performed at the three axial locations of z/D = 12.2, 42.2, and 100.7. The accuracy of the local measurements is assured by integrating the local flow parameters over the flow channel and comparing with the area-averaged measurements by using impedance void meters [27,28] and gas and liquid flow meters. The visualization method using a high-speed camera was applied to investigate the interaction mechanism between phases.…”

Section: Experimental Databasementioning

confidence: 99%

“…Case P3 in Table 5(b) was selected for this study with our new wall lubrication force coefficients. The effect of the grid size was studied using 10,16,20,22,24,26,28, and 30 grid cells in the radial direction, and 40, 80, and 100 grid cells in the axial direction. As shown in Figure 8(a)-(c), the results of local void fraction, phase velocities, and bubble diameter are insensitive to the radial grid size from the value of 20 cells.…”

Section: Grid Sensitivity Studymentioning

confidence: 99%

The dependence of wall lubrication force on liquid velocity in turbulent bubbly two-phase flows

Nguyen

Song

Bae

et al. 2013

Journal of Nuclear Science and Technology

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Based on the significance of a computational fluid dynamics (CFD) simulation of dispersed two-phase flow systems in many engineering fields, especially in nuclear energy systems, extensive analytical and numerical studies of wall lubrication force for vertical upward turbulent bubbly two-phase flow are presented. An analytical expression of the wall lubrication force considering the effect of liquid velocity is developed and analyzed. A numerical methodology for evaluating the wall lubrication force coefficients is proposed, which is based on the assumption that the balance of the forces acting on a bubble perpendicularly to the flow direction determines the establishment of radial void fraction profiles. Wall lubrication force coefficients are determined based on a reasonable agreement in radial void fraction profiles between numerical results predicted by the CFD EAGLE (elaborated analysis of gas-liquid flows evolution) code and extensive experimental database in the open literature as well as experiments performed at the Korea Atomic Energy Research Institute-vertical air-water loop test facility. Liquid velocity dependence of wall lubrication force is clearly shown in both analytical and numerical ways in the present study, and new correlations are then proposed for the wall lubrication force coefficients.

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“…Furthermore, big progress was made in identifying flow patterns based on the differential pressure signal of two-phase flow in the pipe [9][10][11]. Thereafter, many other methods, including wavelet analysis [12][13][14], Hilbert-Huang transform [15], Wigner-Ville distribution [16][17][18], recurrence plot [19,20], complex network [21], and so on were widely used in the analysis of signals obtained from gas-liquid two-phase flow. Besides, the scholars predicted the flow pattern transitional boundaries on the basis of the gas-liquid two-phase flow mechanisms [22][23][24], which, however, are prone to be influenced by the criteria for the flow pattern conversion.…”

Section: Introductionmentioning

confidence: 99%

Multi-Scale Morphological Analysis of Conductance Signals in Vertical Upward Gas–Liquid Two-Phase Flow

Lian

Ren

Han

et al. 2016

Zeitschrift Für Naturforschung A

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Abstract:The multi-scale analysis is an important method for detecting nonlinear systems. In this study, we carry out experiments and measure the fluctuation signals from a rotating electric field conductance sensor with eight electrodes. We first use a recurrence plot to recognise flow patterns in vertical upward gas-liquid two-phase pipe flow from measured signals. Then we apply a multi-scale morphological analysis based on the first-order difference scatter plot to investigate the signals captured from the vertical upward gas-liquid two-phase flow loop test. We find that the invariant scaling exponent extracted from the multi-scale first-order difference scatter plot with the bisector of the second-fourth quadrant as the reference line is sensitive to the inhomogeneous distribution characteristics of the flow structure, and the variation trend of the exponent is helpful to understand the process of breakup and coalescence of the gas phase. In addition, we explore the dynamic mechanism influencing the inhomogeneous distribution of the gas phase in terms of adaptive optimal kernel time-frequency representation. The research indicates that the system energy is a factor influencing the distribution of the gas phase and the multiscale morphological analysis based on the first-order difference scatter plot is an effective method for indicating the inhomogeneous distribution of the gas phase in gasliquid two-phase flow.

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An application of the wavelet analysis technique for the objective discrimination of two-phase flow patterns

Cited by 66 publications

References 27 publications

Monitoring Cavitation Regime From Pressure and Optical Sensors: Comparing Methods Using Wavelet Decomposition for Signal Processing

Monitoring Cavitation Regime From Pressure and Optical Sensors: Comparing Methods Using Wavelet Decomposition for Signal Processing

The dependence of wall lubrication force on liquid velocity in turbulent bubbly two-phase flows

Multi-Scale Morphological Analysis of Conductance Signals in Vertical Upward Gas–Liquid Two-Phase Flow

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