scholarly journals Application of Wavelet Feature Extraction and Artificial Neural Networks for Improving the Performance of Gas–Liquid Two-Phase Flow Meters Used in Oil and Petrochemical Industries

Polymers ◽  
2021 ◽  
Vol 13 (21) ◽  
pp. 3647
Author(s):  
Siavash Hosseini ◽  
Osman Taylan ◽  
Mona Abusurrah ◽  
Thangarajah Akilan ◽  
Ehsan Nazemi ◽  
...  
Keyword(s):  
Feature Extraction ◽  
Wavelet Transform ◽  
Flow Regime ◽  
Void Fraction ◽  
Low Frequency ◽  
Flow Regimes ◽  
Discrete Wavelet ◽  
Two Phase ◽  
Flow Meters ◽  
Petrochemical Industries

Measuring fluid characteristics is of high importance in various industries such as the polymer, petroleum, and petrochemical industries, etc. Flow regime classification and void fraction measurement are essential for predicting the performance of many systems. The efficiency of multiphase flow meters strongly depends on the flow parameters. In this study, MCNP (Monte Carlo N-Particle) code was employed to simulate annular, stratified, and homogeneous regimes. In this approach, two detectors (NaI) were utilized to detect the emitted photons from a cesium-137 source. The registered signals of both detectors were decomposed using a discrete wavelet transform (DWT). Following this, the low-frequency (approximation) and high-frequency (detail) components of the signals were calculated. Finally, various features of the approximation signals were extracted, using the average value, kurtosis, standard deviation (STD), and root mean square (RMS). The extracted features were thoroughly analyzed to find those features which could classify the flow regimes and be utilized as the inputs to a network for improving the efficiency of flow meters. Two different networks were implemented for flow regime classification and void fraction prediction. In the current study, using the wavelet transform and feature extraction approach, the considered flow regimes were classified correctly, and the void fraction percentages were calculated with a mean relative error (MRE) of 0.4%. Although the system presented in this study is proposed for measuring the characteristics of petroleum fluids, it can be easily used for other types of fluids such as polymeric fluids.

Experiment of Adiabatic Two-Phase Flow in an Annulus Under Low-Frequency Vibration

2012 ◽  
Author(s):  
Shao-Wen Chen ◽  
Caleb S. Brooks ◽  
Chris Macke ◽  
Takashi Hibiki ◽  
Mamoru Ishii ◽  
...  
Keyword(s):  
Void Fraction ◽  
Two Phase Flow ◽  
Low Frequency ◽  
Flow Regimes ◽  
Operating Conditions ◽  
Phase Flow ◽  
Two Phase ◽  
Specific Flow ◽  
Low Frequency Vibration ◽  
Fft Analysis

In order to investigate the possible effect of seismic vibration on two-phase flow dynamics and thermal-hydraulics of a nuclear reactor, experimental tests of adiabatic air-water two-phase flow under low-frequency vibration were carried out in this study. An eccentric cam vibration module operated at low motor speed (up to 390rpm) was attached to an annulus test section which was scaled down from a prototypic BWR fuel assembly sub-channel. The inner and outer diameters of the annulus are 19.1mm and 38.1mm, respectively. The two-phase flow operating conditions cover the ranges of 0.03≤<jg> ≤1.46m/s and 0.25≤<jf>≤1.00m/s and the vibration displacement ranges from ±0.8mm to ±22.2mm. Steady-state area-averaged instantaneous and time-averaged void fraction was recorded and analyzed in stationary and vibration experiments. A neural network flow regime identification technique and fast Fourier transformation (FFT) analysis were introduced to analyze the flow regimes and void signals under stationary and vibration conditions. Experimental results reveal possible changes in flow regimes under specific flow and vibration conditions. In addition, the instantaneous void fraction signals were affected and shown by FFT analysis. Possible reasons for the changes include the applied high acceleration and/or induced resonance at certain ports under the specific flow and vibration conditions.

Experimental Study of Adiabatic Two-Phase Flow in an Annular Channel Under Low-Frequency Vibration

2013 ◽  
Vol 136 (3) ◽  
Author(s):  
Shao-Wen Chen ◽  
Takashi Hibiki ◽  
Mamoru Ishii ◽  
Michitsugu Mori ◽  
Fumitoshi Watanabe
Keyword(s):  
Void Fraction ◽  
Two Phase Flow ◽  
Low Frequency ◽  
Flow Regimes ◽  
Operating Conditions ◽  
Phase Flow ◽  
Two Phase ◽  
Specific Flow ◽  
Low Frequency Vibration ◽  
Fft Analysis

In order to investigate the possible effect of seismic vibration on two-phase flow dynamics and thermal-hydraulics of a nuclear reactor, experimental tests of adiabatic air-water two-phase flow under low-frequency vibration were carried out in this study. An eccentric cam vibration module operated at low motor speed (up to 390 rpm) was attached to an annulus test section which was scaled down from a prototypic boiling water reactor (BWR) fuel assembly subchannel. The inner and outer diameters of the annulus are 19.1 mm and 38.1 mm, respectively. The two-phase flow operating conditions cover the ranges of 0.03 m/s ≤ 〈jg〉 ≤ 1.46 m/s and 0.25 m/s ≤ 〈jf〉 ≤ 1.00 m/s and the vibration displacement ranges from ±0.8 mm to ±22.2 mm. Steady-state area-averaged instantaneous and time-averaged void fraction were recorded and analyzed in stationary and vibration experiments. A neural network flow regime identification technique and fast Fourier transformation (FFT) analysis were introduced to analyze the flow regimes and void signals under stationary and vibration conditions. Experimental results reveal possible changes in flow regimes under specific flow and vibration conditions. In addition, the instantaneous void fraction signals were affected and shown by FFT analysis. Possible reasons for the changes include the applied high acceleration and induced void/flow structure changes at certain ports under the specific flow and vibration conditions.

Effect of Flow Regime and Void Fraction on Tube Bundle Vibration

2001 ◽  
Vol 123 (4) ◽  
pp. 407-413 ◽  
Author(s):  
C. E. Taylor ◽  
M. J. Pettigrew
Keyword(s):  
Heat Exchanger ◽  
Flow Regime ◽  
Void Fraction ◽  
Flow Regimes ◽  
Design Guidelines ◽  
Two Phase ◽  
Fluid Forces ◽  
Drift Flux Model ◽  
Test Loop ◽  
Fraction Models

Two-phase cross flow occurs in industrial heat exchangers such as condensers, boilers, and steam generators. Under certain flow regimes and fluid velocities, the fluid forces result in tube vibration and possibly tube damage due to fretting or fatigue. Prediction of these fluid forces requires an understanding of the flow regimes found in heat exchanger tube bundles. Measurements of void fraction within a tube array were taken as an initial step in determining the two-phase flow patterns. The tests were conducted in a Freon 134a test loop at about 1 MPa and 30°C. The measurements were compared against void fraction models commonly used in heat exchanger thermalhydraulic simulation codes and against available flow regime maps. Not surprisingly, the results indicate that a drift-flux model more accurately predicts the void fraction within a tube array. The measurements also confirm the existence of nonuniform void fraction radially around the tube. Based on these measurements and available literature, appropriate void fraction models for use in flow-induced vibration design guidelines are discussed.

Measurement of Void Fraction and Pressure Drop of Air-Oil Two-Phase Flow in Horizontal Pipes

2004 ◽  
Vol 126 (1) ◽  
pp. 107-118 ◽  
Author(s):  
J. L. Pawloski ◽  
C. Y. Ching ◽  
M. Shoukri
Keyword(s):  
Pressure Drop ◽  
Flow Regime ◽  
Void Fraction ◽  
High Speed ◽  
Two Phase Flow ◽  
Flow Regimes ◽  
Phase Flow ◽  
Two Phase ◽  
Wide Range ◽  
Flow Regime Maps

The void fractions, flow regimes, and pressure drop of air-oil two-phase flow in a half-inch diameter pipe over a wide range of test conditions have been investigated. The flow regimes were identified with the aid of a 1000 frames per second high-speed camera. A capacitance sensor for instantaneous void fraction measurements was developed. The mean and probability density function of the instantaneous void fraction signal can be used to effectively identify the different flow regimes. The current flow regime data show significant differences in the transitional boundaries of the existing flow regime maps. Property correction factors for the flow regime maps are recommended. The pressure drop measurements were compared to the predictions from four existing two-phase flow pressure drop models. Though some of the models performed better for certain flow regimes, none of the models were found to give accurate results over the entire range of flow regimes.

Fault detection and flow regime identification based on analysis of signal noise from electromagnetic flowmeters

2001 ◽  
Vol 215 (4) ◽  
pp. 283-294 ◽  
Author(s):  
S Perovic ◽  
E H Higham ◽  
P J Unsworth
Keyword(s):  
Flow Regime ◽  
Swirling Flow ◽  
Low Frequency ◽  
Flow Regimes ◽  
Two Phase ◽  
Measurement Signal ◽  
Frequency Components ◽  
Potential Benefits ◽  
On Line ◽  
Sensor Signals

The signal conditioning and processing circuits of conventional electromagnetic flowmeters have been designed to provide an accurate average flowrate measurement signal, principally for the purpose of process control. One consequence of this is that the ‘noise’ and other low frequency components of the electrode signal are suppressed. Hitherto, the possibility that they may carry potentially useful information has been overlooked, but there are studies which show that information regarding the flow regime can be identified by spectral analysis of the higher frequency or ‘noise’ components of the sensor signals from some other types of flowmeters. If the entire electrode signal is analysed, using well-established signal analysis methods, diagnostic information regarding the flow regime in which the flowmeter is operating can be recovered and several distinctly different flow regimes can be identified, such as increased turbulence, swirling flow, flow pulsations and two-phase flow, all of which adversely affect the performance of the flowmeter. This paper presents the results of laboratory simulations of these flow regimes and describes a fuzzy logic method for identifying them. It also suggests a change to the conventional mode of operation and signal processing which would enable the additional functions to be implemented without involving any modification to the design or construction of the conventional flowtube. The potential benefits which arise from its application include the identification of flow regimes which adversely affect the performance of the flowmeter in its installed position and the ability to verify, on line, that the flowmeter is functioning correctly.

Measurement of Void Fraction and Pressure Drop of Air-Oil Two-Phase Flow in Horizontal Pipes

2002 ◽  
Author(s):  
J. Pawloski ◽  
C. Ching ◽  
M. Shoukri
Keyword(s):  
Pressure Drop ◽  
Flow Regime ◽  
Void Fraction ◽  
High Speed ◽  
Two Phase Flow ◽  
Flow Regimes ◽  
Average Error ◽  
Phase Flow ◽  
Two Phase ◽  
Wide Range

The flow regimes and pressure drop of air-oil two-phase flow in a half-inch diameter pipe over a wide range of test conditions have been investigated. The flow regimes were identified with the aid of a 1000 frames per second high-speed camera. The current flow regime data show significant differences in the transitional boundaries from the flow regime maps of Mandhane et al. (1974), Taitel and Dukler (1974) and Spedding and Nguyen (1980). The pressure drop measurements were compared to the predictions from four existing pressure drop models: Homogeneous, Martinelli (1948), Chisolm (1973) and Olujic (1985). The Chisolm and Martinelli models were found to be the most accurate, with an average error of about 35 percent. A capacitance sensor for instantaneous void fraction measurement was developed. Results indicate the data from the sensor could be used to identify the different flow regimes.

scholarly journals Multi-focus Image Fusion Using an Effective Discrete Wavelet Transform Based Algorithm

2014 ◽  
Vol 14 (2) ◽  
pp. 102-108 ◽  
Author(s):  
Yong Yang ◽  
Shuying Huang ◽  
Junfeng Gao ◽  
Zhongsheng Qian
Keyword(s):  
Wavelet Transform ◽  
Image Fusion ◽  
Discrete Wavelet Transform ◽  
High Frequency ◽  
Low Frequency ◽  
Objective Evaluation ◽  
Discrete Wavelet ◽  
Evaluation Indexes ◽  
Fused Image ◽  
Focus Image

Abstract In this paper, by considering the main objective of multi-focus image fusion and the physical meaning of wavelet coefficients, a discrete wavelet transform (DWT) based fusion technique with a novel coefficients selection algorithm is presented. After the source images are decomposed by DWT, two different window-based fusion rules are separately employed to combine the low frequency and high frequency coefficients. In the method, the coefficients in the low frequency domain with maximum sharpness focus measure are selected as coefficients of the fused image, and a maximum neighboring energy based fusion scheme is proposed to select high frequency sub-bands coefficients. In order to guarantee the homogeneity of the resultant fused image, a consistency verification procedure is applied to the combined coefficients. The performance assessment of the proposed method was conducted in both synthetic and real multi-focus images. Experimental results demonstrate that the proposed method can achieve better visual quality and objective evaluation indexes than several existing fusion methods, thus being an effective multi-focus image fusion method.

Countercurrent Two-Phase Flow Regimes and Void Fraction in Vertical and Inclined Channels

1995 ◽  
Vol 119 (3) ◽  
pp. 182-194 ◽  
Author(s):  
S. M. Ghiaasiaan ◽  
K. E. Taylor ◽  
B. K. Kamboj ◽  
S. I. Abdel-Khalik
Keyword(s):  
Void Fraction ◽  
Two Phase Flow ◽  
Flow Regimes ◽  
Phase Flow ◽  
Two Phase ◽  
Inclined Channels

scholarly journals On Damping and Fluidelastic Instability in a Tube Bundle Subjected to Two-Phase Cross-Flow

2007 ◽  
Author(s):  
Joaquin E. Moran ◽  
David S. Weaver
Keyword(s):  
Flow Regime ◽  
Void Fraction ◽  
Tube Bundle ◽  
Damping Ratio ◽  
Pressure Fluctuations ◽  
Cross Flow ◽  
Phase Changes ◽  
Working Fluid ◽  
Two Phase ◽  
Fluidelastic Instability

An experimental study was conducted to investigate damping and fluidelastic instability in tube arrays subjected to two-phase cross-flow. The purpose of this research was to improve our understanding of these phenomena and how they are affected by void fraction and flow regime. The working fluid used was Freon 11, which better models steam-water than air-water mixtures in terms of vapour-liquid mass ratio as well as permitting phase changes due to pressure fluctuations. The damping measurements were obtained by “plucking” the monitored tube from outside the test section using electromagnets. An exponential function was fitted to the tube decay trace, producing consistent damping measurements and minimizing the effect of frequency shifting due to fluid added mass fluctuations. The void fraction was measured using a gamma densitometer, introducing an improvement over the Homogeneous Equilibrium Model (HEM) in terms of density and velocity predictions. It was found that the Capillary number, when combined with the two-phase damping ratio (interfacial damping), shows a well defined behaviour depending on the flow regime. This observation can be used to develop a better methodology to normalize damping results. The fluidelastic results agree with previously presented data when analyzed using the HEM and the half-power bandwidth method. The interfacial velocity is suggested for fluidelastic studies due to its capability for collapsing the fluidelastic data. The interfacial damping was introduced as a tool to include the effects of flow regime into the stability maps.

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