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A method for bubble volume calculating in vertical two-phase flow

Journal of Physics: Conference Series 2009年第1期147卷

作者： H Y Wang F Dong Tianjin Key Laboratory of Process Measurement and Control School of Electrical Engineering & Automation Tianjin University Tianjin 300072 CHINA

The movement of bubble is a basic subject in gas-liquid two-phase flow research. A method for calculating bubble volume which is one of the most important characters in bubble motion research was proposed. A suit of visualized experimental device was designed and set up. Single bubble rising in stagnant liquid in a rectangular tank was studied using the high-speed video system. Bubbles generated by four orifice with different diameter (1mm, 2mm, 3mm, 4mm) were recorded respectively. Sequences of recorded high-speed images were processed by digital image processing method, such as image noise remove, binary image transform, bubble filling, and so on. then, Several parameters could be obtained from the processed image. Bubble area, equivalent diameter, bubble velocity, bubble acceleration are all indispensable in bubble volume calculating. In order to get the force balance equation, forces that work on bubble along vertical direction, including drag force, virtual mass force, buoyancy, gravity and liquid thrust, were analyzed. Finally, the bubble volume formula could be derived from the force balance equation and bubble parameters. Examples were given to shown the computing process and results. Comparison of the bubble volume calculated by geomettic method and the present method have shown the superiority of the proposed method in this paper.

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Flow rate measurement of oil-water two-phase flow based on V-cone flow meter

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Journal of Physics: Conference Series 2009年第1期147卷

作者： F Dong C Tan W Li F S Zhang Tianjin Key Laboratory of Process Measurement and Control School of Electrical Engineering and Automation Tianjin University Tianjin 300072 CHINA

In petroleum industry, oil-water two-phase flow widely exists in production wells, and the measurement of oil-water flow is significant in oil well logging. One method in common use is to build a theoretic model to connect differential pressures generated by a throttling set with flow-rate. Several measuring models were adopted and compared for model selection and modification. A V-cone with 0.65 diameter ratio was selected as the throttling set because of its special structure and intrinsic advantages. In the experiments, the differential pressures measured under different flow range were processed with a homogeneous flow model. And the results show that the error is small in the condition where the oil and water are well mixed, while the error is big when they are not well mixed. A polynomial of the error and the water percentage was fitted to improve the model accuracy and widen the measurement range.

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Non-crosstalk real-time ultrasonic range system optimized chaotic pulse position-width excitation

Non-crosstalk real-time ultrasonic range system optimized ch...

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2008 IEEE International Ultrasonics Symposium, IUS 2008

作者： Yao, Zhen-Jing Meng, Qing-Hao Li, Gen-Wang Lin, Pu Tianjin Key Laboratory of Process Measurement and Control School of Electrical Engineering and Automation Tianjin University Tianjin China

ISBN: (纸本)9781424424283

Ultrasonic crosstalk is one of the main causes of false measurements that reduce the work efficiency of sonar in mobile robots. To enhance the real-time performance sonar systems, chaotic pulse position-width modulation (CPPWM) sequences are proposed to construct short digital sequences to trigger ultrasonic transducers. Thanks their properties of sharp autocorrelation and flat crosscorrelation, series are used to modulate both pulse and width. To obtain the better echo correlation and the larger echo energy, the Non-dominated Genetic Algorithm-II (NSGA-II) is adopted to optimize pulse periods and pulse duty ratio. Real experiments using 600 series instrument-grade electrostatic transducers the suitability of the proposed method. ©2008 IEEE.

关键词： Mobile robots

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Entropy feature extraction on flow pattern of gas/liquid two-phase flow based on cross-section measurement

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Journal of Physics: Conference Series 2009年第1期147卷

作者： J Han F Dong Y Y Xu Tianjin Key Laboratory of Process Measurement and Control School of Electrical Engineering & Automation Tianjin University Tianjin 300072 CHINA Department of Educational Technology Capital Normal University Beijing 100037 CHINA

This paper introduces the fundamental of cross-section measurement system based on Electrical Resistance Tomography (ERT). The measured data of four flow regimes of the gas/liquid two-phase flow in horizontal pipe flow are obtained by an ERT system. For the measured data, five entropies are extracted to analyze the experimental data according to the different flow regimes, and the analysis method is examined and compared in three different perspectives. The results indicate that three different perspectives of entropy-based feature extraction are sensitive to the flow pattern transition in gas/liquid two-phase flow. By analyzing the results of three different perspectives with the changes of gas/liquid two-phase flow parameters, the dynamic structures of gas/liquid two-phase flow is obtained, and they also provide an efficient supplementary to reveal the flow pattern transition mechanism of gas/liquid two-phase flow. Comparison of the three different methods of feature extraction shows that the appropriate entropy should be used for the identification and prediction of flow regimes.

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Regime recognition of two-phase pipe flow based on D-S evidengce theory

Regime recognition of two-phase pipe flow based on D-S evide...

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7th International Conference on Machine Learning and Cybernetics, ICMLC

作者： Fu-Sheng, Zhang Feng, Dong Chao, Tan Dong, Liu Tianjin Key Laboratory of Process Measurement and Control School of Electrical Engineering and Automation Tianjin University Tianjin 300072 China

ISBN: (纸本)9781424420964

Flow regime recognition plays a fundamental role in two-phase flow measurement. Based on the characters information provided by dual-plane electrical resistance tomography (ERT) system, a method of flow regime recognition in horizontal pipe based on D-S evidence theory is brought forward. A particular way to acquire the basic probability assignment function in D-S evidence theory is introduced. Every single plane of the dual-plane ERT system has been regarded as an independent information resource. Through the fusion of features from both of the planes, less features are needed to be extracted, and better flow regime identifying result is achieved. © 2008 IEEE.

关键词： Two phase flow

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Performance of a Horizontally Mounted Venturi in Low-pressure Wet Gas Flow

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Chinese Journal of Chemical engineering 2008年第2期16卷 320-324页

作者：方立德张涛 Key Laboratory for Process Measurement and Control School of Electrical Engineering and Automation Tianjin University Tianjin 300072 China

The performance of a Venturi tube used in wet gas flow have been explored mainly under higher-pressure condition, but very often, low-pressure test exists in some oil and gas fields in Tianjin Dagang Oil and Gas Field in China. In this study, the performance of horizontally mounted Venturi meters in low-pressure wet gas flow is discussed. Three 50 mm Venturi meters were tested systematically, with fl values of 0.4048, 0.55 and 0.70, the opera- tion pressure of 0.15 MPa, 0.20 MPa, 0.25 MPa, the gas densiometric Froude number from 0.6 to 2.0, the modified Lockhart-Maretinelli parameter from 0.0022 to 0.06, and the ratio of the gas liquid mass flow rate from 0.5 to 0.99. The effects of modified Lockhart-Maretinelli parameter, pressure, gas densiometric Froude number, diameter ratio, and gas-liquid mass flow rate ratio to the Venturi tube are analyzed with new independent data. Furthermore, low-pressure performance was compared with that under high pressure.

关键词： gas-liquid two phase flow wet gas metering Venturi meter over-reading

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Numerical simulation of flow field in a quench oil tower

Numerical simulation of flow field in a quench oil tower

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2007 ASME Pressure Vessels and Piping Conference, PVP 2007

作者： Shuihua, Zheng Shengchang, Zhang Zengliang, Gao Zhejiang University of Technology Institute of Process Equipment and Control Engineering MOE Key Laboratory of Mechanical Manufacture and Automation Hangzhou 310032 China

ISBN: (纸本)0791842819

Towers are applied in the wide range of the petrochemical industry. The flow condition and the temperature distribution in the tower are the focus of the people's attention, which would affect function of the tower and could result in unstable operation of the tower. In this paper, the flow field in a quench oil tower is simulated based on CFD method. The DPM (Discrete Phase Model) is used to calculate and analyze flow distribution and heat transfer between gas and liquid. The numerical results such as temperature and velocity distributions below lower tray in tower are obtained. According to CFD results, modification method of improving the flow distribution is proposed. Copyright © 2007 by ASME.

关键词： Flow fields

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Research on the vibratory stress relief used to reduce residual stress of mismatch butt welds of a cylinder

Research on the vibratory stress relief used to reduce resid...

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2007 ASME Pressure Vessels and Piping Conference, PVP 2007

作者： Xin, Ren Yuan, Tian Zengliang, Gao Kangda, Zhang Zhejiang University of Technology Institute of Process Equipment and Control Engineering MOE Key Laboratory of Mechanical Manufacture and Automation Hangzhou 310032 China

ISBN: (纸本)0791842843

The residual stresses of mismatch butt welds of a cylinder were measured by the blind-hole method before and after a vibratory residual stress relief treatment. The results show that this treatment could greatly reduce the maximal butt weld residual stress of dissimilar steel from 540MPa to 119MPa. The concentrated distributions of the first and the second principal residual stresses became gentle after the vibratory residual stress relief treatment. Copyright © 2007 by ASME.

关键词： Stress analysis

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Experimental study of position of piezoelectric probe in vortex row sensor

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Jiliang Xuebao/Acta Metrologica Sinica 2008年第5期29卷 427-433页

作者： Zheng, Dan-Dan Zhang, Tao Tianjin Key Laboratory of Process Measurement and Control School of Electrical Engineering and Automation Tianjin University Tianjin 300072 China

The design of bluff body, signal detection and processing methods of vortex flow sensors have been discussed by many researchers. The position of piezoelectric pressure probe in vortex flow sensor is seldom investigated. Experiments are firstly carried out in a water channel and a wind tunnel. It is found that the amplitude and frequency of vortex signals are closely related to locations of the probe, and positions of most intensive signals are different to bluff bodies with various width. Furthermore, experiments are carried out in a pipe to analyze the regularity of vortex signals. The differences between two-dimensional and three-dimensional vortex flow fields are compared and explained by numerical simulations. Finally, the optimum detecting position in vortex flow sensor is determined: the optimum distance between bluff body and probe is equal to the width of bluff body. In order to prove the conclusion, calibration tests are made on water and air standard flow equipments with DN100 and DN50 vortex flow sensors respectively. The linearity and repeatability of vortex flow sensor are both improved.

关键词： Metrology Numerical simulation Piezoelectric probe Signal intensity Vortex flow sensor

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A unified approach to fuzzy modelling and robust synchronization of different hyperchaotic systems

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Chinese Physics B 2008年第11期17卷 4056-4066页

作者： Zhang, Hua-Guang Zhao, Yan Yu, Wen Yang, Dong-Sheng School of Information Science and Engineering Northeastern University Shenyang 110004 China Key Laboratory of Integrated Automation of Process Industry Ministry of Education Northeastern University Shenyang 110004 China Department of Automatic Control Engineering Shenyang Institute of Engineering Shenyang 110136 China Departamento de Control Automatico CINVESTAV-IPN Av. IPN 2508 México D. F. 07360 Mexico

In this paper, a Takagi-Sugeno (T-S) fuzzy model-based method is proposed to deal with the problem of synchronization of two identical or different hyperchaotic systems. The T-S fuzzy models with a small number of fuzzy IF-THEN rules are employed to represent many typical hyperchaotic systems exactly. The benefit of employing the T-S fuzzy models lies in mathematical simplicity of analysis. Based on the T-S fuzzy hyperchaotic models, two fuzzy controllers are designed via parallel distributed compensation (PDC) and exact linearization (EL) techniques to synchronize two identical hyperchaotic systems with uncertain parameters and two different hyperchaotic systems, respectively. The sufficient conditions for the robust synchronization of two identical hyperchaotic systems with uncertain parameters and the asymptotic synchronization of two different hyperchaotic systems are derived by applying the Lyapunov stability theory. This method is a universal one of synchronizing two identical or different hyperchaotic systems. Numerical examples are given to demonstrate the validity of the proposed fuzzy model and hyperchaotic synchronization scheme. © 2008 Chin. Phys. Soc. and IOP Publishing Ltd.

关键词： Synchronization

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