Gas-liquid two phase flow pattern evolution characteristics based on detrended fluctuation analysis

Zhai, Lusheng; Jin, Ningde; Gao, Zhong-Ke; Chi, Heng

doi:10.1007/s12647-011-0024-3

Cited by 3 publications

(3 citation statements)

References 13 publications

(14 reference statements)

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“…For locating long-range correlation and power-law behavior in nonlinear time series data, Detrended Fluctuation Analysis (DFA) has become a popular and dependable method [23]. In this regard, Zhai et al presented the fractal scales for various flow patterns by using DFA to study gas-liquid twophase flow [24]. Hernández et al discovered that the multifractal DFA method enabled the accurate recognition of the distinct energy levels present in the gas-liquid two-phase flow, in accordance with the observed flow patterns at different locations [25].…”

Section: Introductionmentioning

confidence: 99%

Multifractal magnitude and sign correlations in multiphase flows

Ren,

Jin

2024

Meas. Sci. Technol.

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It is important to reveal the complex phenomenon of bubble coalescence or breakup in gas-liquid two-phase flow to understand the dynamic mechanism of flow pattern transition. Magnitude and sign decomposition pave a way to study the linear and nonlinear fractal characteristic separately. In this work, we extend this method to multifractal analysis, namely the multifractal magnitude and sign correlations. Test was conducted and an eight-electrode rotating conductivity sensor is utilized to collect the signals of different flow patterns in the gas-liquid two phase flow. The signal is initially decomposed into magnitude time series and sign time series. The width and difference of multifractal spectrums are introduced to characterize the nonlinear dynamics in the flow pattern evolution that gas-liquid two-phase slug flow breaks into the bubble flow or loses stability transforms into churn flow. And then these two parameters of multifractal magnitude and sign decomposition are fed into k-Nearest Neighbor for flow pattern identification. The results suggest that multifractal magnitude and sign decomposition has higher prediction accuracy (93%) than traditional multifractal analysis. The findings show that multifractal magnitude and sign correlations analysis is a powerful technique for investigating the flow dynamic of gas-liquid two phase flow.

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Section: Introductionmentioning

confidence: 99%

Multifractal magnitude and sign correlations in multiphase flows

Ren,

Jin

2024

Meas. Sci. Technol.

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“…Even though different methods were applied in the past to investigate low viscosity two-phase flows, only the work by Zahi et al [14] concerns the use of DFA (to the best of our knowledge). As a matter of fact, these authors compared various fractal methods with the DFA.…”

Section: Introductionmentioning

confidence: 99%

“…More importantly, the DFA was shown to perform better in comparison with other fractal techniques with varying noise levels. Therefore, Zahi et al [14] concluded that the DFA based approach can effectively underline the flow pattern characteristics. The ability of the method to provide information of the transitions was also stressed.…”

Section: Introductionmentioning

confidence: 99%

Evolution of High-Viscosity Gas–Liquid Flows as Viewed Through a Detrended Fluctuation Characterization

et al. 2019

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We characterize the long-term development of high-viscosity gas–liquid intermittent flows by means of a detrended fluctuation analysis (DFA). To this end, the pressures measured at different locations along an ad hoc experimental flow line are compared. We then analyze the relevant time-series to determine the evolution of the various kinds of intermittent flow patterns associated with the mixtures under consideration. Although no pattern transitions are observed in the presence of high-viscosity mixtures, we show that the dynamical attributes of each kind of intermittence evolves from one point to another within the transport system. The analysis indicates that the loss of a long-range correlation between the pressure responses are due to the discharge processes.

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Multi-scale cross-correlation characteristics of void fraction wave propagation for gas-liquid two-phase flows in small diameter pipe

Zhai¹,

Jin²

2016

Acta Phys. Sin.

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The void fraction wave is a special physical phenomenon in a gas-liquid two-phase flow system. Understanding the propagation of the void fraction wave is of great significance for uncovering the physical mechanisms in both flow pattern transition and the fluid velocity measurement. In this study, detrended cross-correlation analysis (DCCA) is used to investigate the multi-scale cross-correlation characteristics of the coupled ARFIMA processes. It is found that the DCCA can effectively reveal the multi-scale cross-correlation dynamical behaviors of complex system. Then, we carry out the experimental test in a vertical gas-liquid two-phase flow pipe with small inner diameter. The DCCA is used to detect the cross-correlation characteristics of the void fraction wave on multiple time scales, and the growth rate of the cross-correlation level for the void fraction wave is observed on low time scales. Additionally, the spatial attenuation factor (SAF) of the void fraction wave is calculated to investigate the instability of the wave propagation. The SAF is close to zero under the transitional flow patterns, which means that the void fraction wave is in a stable propagating state. For bubble flows, the void fraction wave presents the attenuation characteristics, whilst the void fraction wave shows the amplification characteristics under the slug and churn flow patterns. Interestingly, the instability behaviors of the void fraction wave are always associated with its multi-scale cross-correlation characteristics. Specifically, the increasing rate of the wave cross-correlation level on low scales is much higher for transitional flow patterns, which is corresponding to the stable propagating characteristic of the void fraction wave. However, when the void fraction wave exhibits attenuation or amplification characteristics under other flow patterns, the increasing rate of the wave cross-correlation level on low scales is much lower.

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Gas-liquid two phase flow pattern evolution characteristics based on detrended fluctuation analysis

Cited by 3 publications

References 13 publications

Multifractal magnitude and sign correlations in multiphase flows

Multifractal magnitude and sign correlations in multiphase flows

Evolution of High-Viscosity Gas–Liquid Flows as Viewed Through a Detrended Fluctuation Characterization

Multi-scale cross-correlation characteristics of void fraction wave propagation for gas-liquid two-phase flows in small diameter pipe

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