Analysis of the dynamic characteristics of air-water two-phase flow in small channel based on multi-scale normalized Benford probability distribution

2018 ◽  
Vol 179 ◽  
pp. 161-171 ◽  
Author(s):  
Hong-Wei Li ◽  
Hao-Fei Pei ◽  
Di Yang ◽  
Bin Sun ◽  
Yun-Long Zhou
Keyword(s):  
Probability Distribution ◽  
Dynamic Characteristics ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Two Phase ◽  
Multi Scale ◽  
Small Channel

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

Entropy ◽  
2019 ◽  
Vol 21 (7) ◽  
pp. 667 ◽  
Author(s):  
Bo Sun ◽  
He Chang ◽  
Yun-Long Zhou
Keyword(s):  
Working Conditions ◽  
Dynamic Characteristics ◽  
Two Phase Flow ◽  
Flow Regimes ◽  
Horizontal Channel ◽  
Phase Flow ◽  
Two Phase ◽  
Multi Scale ◽  
Wide Range ◽  
Vibration Parameters

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.

Multi-scale symbolic time reverse analysis of gas–liquid two-phase flow structures

2017 ◽  
Vol 28 (01) ◽  
pp. 1750007 ◽  
Author(s):  
Hongmei Wang ◽  
Lusheng Zhai ◽  
Ningde Jin ◽  
Youchen Wang
Keyword(s):  
Nonlinear Systems ◽  
Dynamic Characteristics ◽  
Two Phase Flow ◽  
Flow Structures ◽  
Phase Flow ◽  
Two Phase Flows ◽  
Two Phase ◽  
Multi Scale ◽  
Flow Parameters ◽  
Complex Nonlinear Systems

Gas–liquid two-phase flows are widely encountered in production processes of petroleum and chemical industry. Understanding the dynamic characteristics of multi-scale gas–liquid two-phase flow structures is of great significance for the optimization of production process and the measurement of flow parameters. In this paper, we propose a method of multi-scale symbolic time reverse (MSTR) analysis for gas–liquid two-phase flows. First, through extracting four time reverse asymmetry measures (TRAMs), i.e. Euclidean distance, difference entropy, percentage of constant words and percentage of reversible words, the time reverse asymmetry (TRA) behaviors of typical nonlinear systems are investigated from the perspective of multi-scale analysis, and the results show that the TRAMs are sensitive to the changing of dynamic characteristics underlying the complex nonlinear systems. Then, the MSTR analysis is used to study the conductance signals from gas–liquid two-phase flows. It is found that the multi-scale TRA analysis can effectively reveal the multi-scale structure characteristics and nonlinear evolution properties of the flow structures.

Multi-scale modeling of dispersed gas–liquid two-phase flow

2004 ◽  
Vol 59 (8-9) ◽  
pp. 1853-1861 ◽  
Author(s):  
N.G. Deen ◽  
M. van Sint Annaland ◽  
J.A.M. Kuipers
Keyword(s):  
Two Phase Flow ◽  
Phase Flow ◽  
Two Phase ◽  
Multi Scale ◽  
Scale Modeling ◽  
Multi Scale Modeling

Measuring Flow Pattern Asymmetry of Oil-Water Two Phase Flows Using Multi-channel Rotating Electric Field Conductance Signals

2018 ◽  
Vol 74 (1) ◽  
pp. 25-41 ◽  
Author(s):  
Yuansheng He ◽  
Yingyu Ren ◽  
Yunfeng Han ◽  
Ningde Jin
Keyword(s):  
Electric Field ◽  
Flow Pattern ◽  
Cross Section ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Two Phase ◽  
Time Asymmetry ◽  
Pipe Cross Section ◽  
Multi Scale ◽  
Oil Water

AbstractThe present study is a report on the asymmetry of dispersed oil phase in vertical upward oil-water two phase flow. The multi-channel signals of the rotating electric field conductance sensor with eight electrodes are collected in a 20-mm inner diameter pipe, and typical images of low pattern are captured using a high speed camera. With the multi-channel rotating electric field conductance signals collected at pipe cross section, multi-scale time asymmetry (MSA) and an algorithm of multi-scale first-order difference scatter plot are employed to uncover the fluid dynamics of oil-water two phase flow. The results indicate that MSA can characterise the non-linear behaviours of oil-water two phase flow. Besides, the MSA analysis also beneficial for understanding the underlying inhomogeneous distribution of the flow pattern in different directions at pipe cross section.

Detecting the Flow Pattern Transition in the Gas-Liquid Two-Phase Flow Using Multivariate Multi-Scale Entropy Analysis

2019 ◽  
Vol 74 (10) ◽  
pp. 837-848 ◽  
Author(s):  
Yudong Liu ◽  
Dayang Wang ◽  
Yingyu Ren ◽  
Ningde Jin
Keyword(s):  
Flow Pattern ◽  
Two Phase Flow ◽  
Flow Patterns ◽  
Mean Value ◽  
Entropy Rate ◽  
Permutation Entropy ◽  
Phase Flow ◽  
Two Phase ◽  
Multi Scale ◽  
Flow Pattern Transition

AbstractDue to the complex flow structure and non-uniform phase distribution in the vertical upward gas-liquid two-phase flow, an eight-electrode rotating electric field conductance sensor is used to obtain multi-channel conductance signals. The flow patterns of the vertical upward gas-liquid two-phase flow are classified according to the images obtained from a high-speed camera. Then, we employ the multivariate weighted multi-scale permutation entropy (MWMPE) to detect the instability of flow pattern transition in the gas-liquid two-phase flow. Afterwards, we compare the results of the MWMPE with those of the single-channel weighted multi-scale permutation entropy (SCWMPE) and multivariate multi-scale sample entropy (MMSE). The comparison results indicate that, compared with the SCWMPE and MMSE, the MWMPE has superior performance in terms of the high-resolution presentation of flow instability in the gas-liquid two-phase flow. Finally, we extract the mean value of the MWMPE in whole scales and the entropy rate of the MWMPE in the small scales. The results indicate that the normalized mean value and normalized entropy rate of MWMPE are very sensitive to the transitions of flow patterns, thus allowing the detection of the instability of flow pattern transition.

Multi-scale Chaotic Analysis of the Characteristics of Gas-Liquid Two-phase Flow Patterns

2010 ◽  
Vol 18 (5) ◽  
pp. 880-888 ◽  
Author(s):  
Hongwei LI ◽  
Yunlong ZHOU ◽  
Bin SUN ◽  
Yue YANG
Keyword(s):  
Two Phase Flow ◽  
Flow Patterns ◽  
Phase Flow ◽  
Two Phase ◽  
Multi Scale

Development of Models Correlating Vibration Excitation Forces to Dynamic Characteristics of Two-Phase Flow in a Tube Bundle

2007 ◽  
Author(s):  
C. Zhang ◽  
M. J. Pettigrew ◽  
N. W. Mureithi
Keyword(s):  
Dynamic Characteristics ◽  
Two Phase Flow ◽  
Tube Bundle ◽  
Flow Path ◽  
Main Flow ◽  
Phase Flow ◽  
Two Phase ◽  
Drag Forces ◽  
Vibration Excitation ◽  
Lift Forces

Recent experiments reveal that somewhat unexpected but significant quasi-periodic forces in both the drag and lift directions existed in a rotated triangular tube bundle subjected to two-phase cross flow. The quasi-periodic drag forces appear to be related to the momentum flux fluctuations in the main flow path between the cylinders. The quasi-periodic lift forces, on the other hand, are mostly correlated to the oscillation in the wake of the cylinders. The objective of this work is to develop semi-analytical models for correlating vibration excitation forces to dynamic characteristics of two-phase flow in a rotated triangular tube bundle and understanding the nature of vibration excitation forces. The relationships between the lift or drag forces and the dynamic characteristics of two-phase flow are established through fluid mechanics momentum equations. A model has been developed to correlate the void fraction fluctuation in the main flow path and the dynamic drag forces. A second model has been developed for correlating the oscillation in the wake of the cylinders and the dynamic lift forces. Although still preliminary, each model can predict the corresponding forces relatively well.

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