Flow pattern map and multi-scale entropy analysis in 3 × 3 rod bundle channel

Zhou, Yunlong; Hou, Yandong; Li, Hongwei; Sun, Bin; Yang, Di

doi:10.1016/j.anucene.2015.02.006

Cited by 36 publications

(4 citation statements)

References 21 publications

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“…Zhang et al (2017) studied single-phase convection and steam-water two-phase flow boiling in a vertical rod bundle, and developed new correlations to predict single-phase heat transfer and two-phase flow boiling heat transfer coefficients. Zhou et al (2015) used the differential pressure signal of the steam-liquid two-phase flow, multi-scale entropy algorithm is employed to reveal the dynamic characteristics of the different flow patterns in the rod bundle. Li et al (2014) analyzed the flow characteristics of vertical upward two-phase flow in small rectangular channels, and proposed two time-frequency representation-based methods (i.e., AOK TFR and DA SFBW) to characterize quantitatively the dynamics behavior of different nitrogen-water two-phase flow patterns.…”

Section: Introductionmentioning

confidence: 99%

Hierarchical entropy analysis for flow pattern of steam-liquid two phase flow in a rod bundle

Zhang

Hou

et al. 2023

Front. Energy Res.

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Flow pattern is very key parameter in the study of flow characteristics and heat transfer characteristics of two-phase flow. In this Paper, two-phase boiling experiment in a 3×3 rod bundle was conducted within the following parameter range: 0≤G≤600kg/(m2⋅s),0.1≤p≤0.12MPa,10≤ΔTsub≤30℃. We first observed the four typical flow patterns, including bubble flow, bubble-churn flow, churn flow, annular flow, and the physical characteristics were studied and the corresponding differential pressure fluctuation signals measured for the four typical flow patterns. The dynamic characteristic of typical flow pattern was investigated by the of hierarchical entropy algorithm. Then the hierarchical entropy value of different flow patterns was calculated. The results indicate that the hierarchical entropy has a better ability to resist noise, and can reveal dynamics complexity of different flow pattern in rod bundle.

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Section: Introductionmentioning

confidence: 99%

Hierarchical entropy analysis for flow pattern of steam-liquid two phase flow in a rod bundle

Zhang

Hou

et al. 2023

Front. Energy Res.

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“…Zhou et al [ 21 ] successfully applied multi-scale entropy theory to analyze differential pressure signals in a 3 × 3 bundle channel, showing a good robustness of revealing the complexity of a signal. Li et al [ 22 ] carried out the symbolic dynamics information entropy extraction of the conductance signals of conventional gas-liquid two-phase flow and analyzed their dynamic typical flow pattern behavior characteristics.…”

Section: Introductionmentioning

confidence: 99%

Flow Regime Recognition and Dynamic Characteristics Analysis of Air-Water Flow in Horizontal Channel under Nonlinear Oscillation Based on Multi-Scale Entropy

Sun

Zhou

2019

Entropy

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Gas-liquid two-phase flow behavior in horizontal channel under heaving motion showed unique dynamic characteristics due to the complex nonlinear interaction. To further establish a description model and investigate the effects of heaving motion on horizontal gas-liquid flow, experiments in a wide range of vibration parameters and working conditions were carried out by combining vibration platform with two-phase flow loop. It was found that the flow regimes under heaving motion showed significant differences compared to the ones expected in steady state flow under the same working conditions. Increasing vibration parameters showed an obvious impact on fluctuation degree of gas-liquid interface by visualizing high-speed photographs. A method based on multi-scale entropy was applied to identify flow regimes and reveal the underlying dynamic characteristics by collecting signals of pressure-difference. The results indicated that the proposed method was effective to analyze gas-liquid two-phase flow transition in horizontal channel under heaving motion by incorporating information of flow condition and change rate of multi-scale entropy, which provided a reliable guide for flow pattern control design and safe operation of equipment. However, for slug-wave and boiling wave flow, an innovative method based on multi-scale marginal spectrum entropy showed more feasible for identification of transition boundary.

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“…Electrical conductivity probes have been used in the past to investigate void fraction, gas velocity and other information of the two-phase mixture and they were also utilized in this study to measure local void fraction. Zhou et al [4] performed steam-water experiments in 3 × 3 heated rod bundles at atmospheric condition and they investigated four flow regimes, including bubble, bubble-churn, churn and annular flow. However, because of the surface instability, slug flow could not be observed.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study of Air–water Two-phase Flow in a 3×3 Rod Bundle for PDF Analysis

Ruan¹,

Yu²,

Chen³

et al. 2019

Proceedings of the 4th World Congress on Momentum, Heat and Mass Transfer

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The objective of this study is to investigate the void fraction distributions by examining the Probability Distribution Function (PDF) of local void fraction in a 3x3 rod bundle geometry. A series of experiment has been carried out with air-water two-phase flow. The experimental tests were performed under the flow conditions of Jg = 0.076-0.24 m/s and Jf = 0.14, 0.19 and 0.24m/s. Two sets of conductivity probe arrangements were used to measure the local void fractions in the regions of "rod-gap" and "sub-channel". It was observed that while the superficial gas velocity increases, the peak regions of probability distribution function may become broadened; whereas the peak values of PDF may be shifted to the left as superficial liquid velocity increases. In addition, the PDF peak values of both regions tended to stay closer and become more overlapped with increasing superficial gas and liquid velocities.

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Flow pattern map and multi-scale entropy analysis in 3 × 3 rod bundle channel

Cited by 36 publications

References 21 publications

Hierarchical entropy analysis for flow pattern of steam-liquid two phase flow in a rod bundle

Hierarchical entropy analysis for flow pattern of steam-liquid two phase flow in a rod bundle

Flow Regime Recognition and Dynamic Characteristics Analysis of Air-Water Flow in Horizontal Channel under Nonlinear Oscillation Based on Multi-Scale Entropy

Experimental Study of Air–water Two-phase Flow in a 3×3 Rod Bundle for PDF Analysis

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