The nonlinear analysis of horizontal oil-water two-phase flow in a small diameter pipe

• Published in: International journal of multiphase flow Vol. 92; pp. 39 - 49
• Main Authors: Zhai, Lu-Sheng, Angeli, Panagiota, Jin, Ning-De, Zhou, Da-Shi, Zhu, Lei
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.06.2017
• Subjects: Flow pattern identification; Flow structure; Horizontal oil-water two-phase flow; Magnitude and sign correlations; Transfer entropy; Flow pattern identification; Transfer entropy; Horizontal oil-water two-phase flow; Flow structure; Magnitude and sign correlations
• ISSN: 0301-9322; 1879-3533
• DOI: 10.1016/j.ijmultiphaseflow.2017.02.006

•Conductance probe signals are collected from horizontal oil-water two-phase flows in a small diameter pipe.•The scaling behaviors of different flow structures are revealed using magnitude and sign detrended fluctuation analysis.•The flow patterns are indentified according to the magnitude and sign scaling exponents at different time scales.•Transfer entropy in a state space is used to uncover the nonlinear dynamic revolution characteristics underlying various flow structures. Horizontal oil-water two-phase flows are frequently encountered in many industrial processes but the understanding of the dynamic behavior underlying the different flow patterns is still a challenge. In this study, we first conduct experiments of horizontal oil-water flows in a small diameter pipe, and collect the fluctuation signals from conductance probes. The multi-scale power-law correlations of the oil-water flow structures are investigated using detrended fluctuation analysis (DFA) based on the magnitude and sign decomposition of the raw signals. The analysis reveals the scaling behavior of different flow structures; five conductive flow patterns are indentified based on the magnitude and sign scaling exponents at different time scales. In addition, the transfer entropy (TE) in a state space is used to study the information transferring characteristics of the oil-water mixture flowing past a conductance cross-correlation velocity probe. The results of TE indicate that the transferring information depends on the flow conditions and can be used to show changes in the flow patterns.