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Chinese control and Decision Conference, CCDC

作者： Xiaoke Li Feng Dong Yan Fu Tianjin Key Laboratory of Process Measurement and Control School of Electrical Engineering and Automation Tianjin University Tianjin China

A current source is one of the most important circuits in Electrical Impedance Tomography (EIT) hardware systems for measuring conductive multiphase flows. One of its important and challenging features is to deliver a relatively large and constant current for a wide range of resistive loads, high signal to noise ratio, and a large bandwidth. To resolve this problem, three different current sources are discussed and compared. They are the Howland current source, an enhanced Howland current source and a dual op-amp current source. The constant-current characteristics is analyzed and compared in circuit principle. Simulation and experimental results show that the enhanced Howland is most stable among the three current sources when the frequency or load changes. Initial tests have proven the feasibility of EIT system with the enhanced Howland current source.

关键词： Impedance Tomography Resistors Voltage measurement Resistance Current measurement Electrodes

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The dynamic compensation of temperature sensors in sonic nozzle airflow standard facilities based on method of positive pressure

The dynamic compensation of temperature sensors in sonic noz...

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IEEE Instrumentation and Measurement Technology Conference

作者： Chao Wang Hongbing Ding Qin Liu Huaxiang Wang Tianjin Key Laboratory of Process Measurement and Control School of Electrical Engineering and Automation Tianjin University Tianjin China

Pt-resistance temperature sensors are very often used in gas-supply systems, and the sonic nozzle airflow standard facilities are no exception. In order to improve dynamic response of Pt thermal resistances and obtain the detailed variation of temperature in pipeline and stagnation tank of airflow standard facility, a realization technique of the temperature compensation, using the model of heat transfer to acquire regularity of temperature change, solving the actual model of Pt thermal resistances and parameters of inverse model by particle swarm optimization algorithm and wavelet filtering algorithm, has been presented in detail. The experimental and simulation results demonstrate the correctness and effectiveness of this compensation method.

关键词： Heat transfer Temperature sensors Thermal resistance Standards Fluids Heating Temperature measurement

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Annular field-focusing capacitance sensor for visualization of the two phase flows

Annular field-focusing capacitance sensor for visualization ...

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IEEE Instrumentation and Measurement Technology Conference

作者： Zhiqiang Zhang Chao Tan Shangjie Ren Yuchen Bian Feng Dong Tianjin Key Laboratory of Process Measurement and Control School of Electrical Engineering and Automation Tianjin University Tianjin China

In this work, the construction of a field-focusing capacitance sensor geometry in the pipeline for monitoring the multiphase flow of non-conductive materials is presented. With a built-in cone, the annular flew field is formed. The sensor geometry has the electrodes around the built-in cone and the inner wall of the tube for forming the field-focusing capacitance measurement form in annular field. Two typical sensitivity maps for the annular field-focusing geometry were calculated with a finite element approach and some typical situation with the sensitivity feature are discussed. Using the multiplexed excitation and parallel measurement scheme, the capacitance of the fluid in the sub-region which defined by the field-focusing sensor in the annular pipe is measured. The prototype sensor is formed by 16 by 16 electrodes, presenting a total of 256 sub-domain capacitance measurements. The annular field flow images can be obtained from the raw measurement data directly. Three annular field two phase flow types are used to carry out simulation experiments and the imaging capability is tested.

关键词： Electrodes Capacitance Capacitance measurement Permittivity Sensitivity Imaging Shape

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Application of PLC for arranging bottle in Beer filling production line

Application of PLC for arranging bottle in Beer filling prod...

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Chinese control and Decision Conference, CCDC

作者： Tianxia Zhang Feng Dong Hao Yuan Tianjin Key Laboratory of Process Measurement and Control School of Electrical Engineering and Automation Tianjin University Tianjin China

In order to make the operation of Beer filling production line automatic and efficient, the control of each subsection needs to be optimized. Arranging bottle is the first subsection of the beer filling production line. And the realization of its control function plays an important role in the smooth operation of the entire production line. To address the issue of the automatic control problems in the arranging bottle process, PLC (programmable logic controller) technology is applied to realize the design of the control system architecture and control procedures. In the project of the control system, depending on the operating state, the functions of the motors and solenoid valves, which are the key parts, are designed. According to the different operation, timely adjustments are made to improve the system efficiency. Meanwhile, on the basis of the monitoring of the operational status and the design of the program, the system faults are diagnosed, and the appropriate control treatments are made, which achieves an automatic, efficient and stable operation of the arranging bottle process.

关键词： Belts Solenoids Valves Sensors Induction motors process control

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A simulation experimental system of multiphase pipe flow

A simulation experimental system of multiphase pipe flow

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Chinese control and Decision Conference, CCDC

作者： Hao Wu Chao Tan Feng Dong Tianjin Key Laboratory of Process Measurement and Control School of Electrical Engineering and Automation Tianjin University Tianjin China

Multiphase flow phenomena are widespread in nature and production process. The study of the flow mechanism and characteristics are a very important in the multiphase pipe flow. The establishment of multiphase flow experimental devices and systems is necessary in the study. In order to multi-phase pipe flow simulation, the small-scale physical experimental system based on the PLC control, and the experimental simulation system of based on Configuration software design are achieved. The physical experimental system can be achieved signals acquisition and control. Bubble flow, stratified flow, wavy flow, slug flow and other flow patterns can be formed in the experimental pipeline by changing the oil-gas-water flow rate. The virtual experimental system consists of the control interface and virtual physical interface. The simulation experiments of the multiphase flow generation can be achieved through the data exchange by two computers. This system meets the requirements for multiphase flow experiment.

关键词： Pipelines Valves Software control systems Computers Data models

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Comparation of calibration methods for bubbly flow video image

Comparation of calibration methods for bubbly flow video ima...

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Chinese control and Decision Conference, CCDC

作者： Weida Zhang Yuchen Bian Feng Dong Tianjin Key Laboratory of Process Measurement and Control School of Electrical Engineering and Automation Tianjin University Tianjin China

Bubble flow video imaging device uses two high speed cameras to capture the bubble rising process in a transparent still sink. Tsai's two step calibration method, Zhang Zhengyou calibration method, Camera Calibration Toolbox for Matlab are selected to do the calibration experiments on the high speed cameras. Each calibration method gives a different calibrated model. The accuracy of different model is compared. It's proved that Zhang's calibration method gives the most accurate model in this experiment. The fundamental of different calibration methods are given at the beginning. The calibrated model given by Zhang's method is used to revise bubble parameters extracted from bubble flow images.

关键词： Calibration Cameras Mathematical model Accuracy Lenses Nonlinear distortion

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Development of a water flow diverter with dividing body driven by stepping motor

Development of a water flow diverter with dividing body driv...

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2012 2nd International Conference on Consumer Electronics, Communications and Networks, CECNet 2012

作者： Li, Shengjie Sun, Lijun Zhang, Tao Qi, Lei Liu, Yi Tianjin Key Laboratory of Process Measurement and Control School of Electrical Engineering and Automation Tianjin University Tianjin China

ISBN: (纸本)9781457714153

A water flow diverter is an essential and error determining component of a liquid flow facility based on a static gravimetric system with flying start and finish. A new diverter was developed in order to reduce the uncertainty, noise and vibration by using a stepping motor to drive the dividing body. The reasons of the diverter timing error and test methods were studied. It is shown by the test results that the uncertainty of the diverter is better than 0.007%. © 2012 IEEE.

关键词： Stepping motors

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Effect of sensing field distribution for EMT basing on sensitivity

Effect of sensing field distribution for EMT basing on sensi...

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IEEE Instrumentation and Measurement Technology Conference

作者： Yan Fu Feng Dong Chao Tan Tianjin Key Laboratory of Process Measurement and Control School of Electrical Engineering and Automation Tianjin University Tianjin China

Electromagnetic tomography (EMT) is of potentially practical value in the field of both industrial and biomedical detection. However, the sensitivity of the sensor array on the changes of the object field distribution, sensitivity and accuracy of the system, measurement precision and system stability are highly dependent on excitation condition. In this paper, the excitation condition of EMT is analyzed with COMSOL Multiphysics the finite element analysis software, the effect can be discussed in two aspects. One is the direct effect on the measurement results from the change of the excitation condition; another is the changing affect on the distribution of integrated sensing field. In this paper, two elements were set which would lead to the change of the excitation condition, the excitation frequency and the excitation strategy. These two elements would affect the sensing field from diverse aspects.

关键词： Sensitivity Coils Sensors Magnetic field measurement Eigenvalues and eigenfunctions Mathematical model Equations

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Investigation on pressure-tapping methods of long waist cone flow meter using CFD simulation

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AIP Conference Proceedings 2012年第1期1428卷 342-349页

作者： Can Wei Chao Tan Feng Dong Xuelian Yu Tianjin Key Laboratory of Process Measurement and Control School of Electrical Engineering and Automation Tianjin University Tianjin 300072 China No.92 Weijin Road China

Differential pressure (DP) flow meters are playing an increasingly important role in multiphase flow in petroleum industry. The long waist cone flow meter, as a new type of DP flow meter, is introduced in this paper. And its flow field in a horizontal pipe of 50mm diameter is numerically simulated with Computational Fluid Dynamics (CFD), in search of the optimum pressure-tapping method. The results of numerical simulations indicate that the long waist cone flow meter has the merits of the annular channel flow meters by forming an annular flow in annular channel region, which makes it possible to improve the repeatability and accuracy of measurement. The high pressure port at the 1D upstream of the cone's entrance section and the low pressure port at the middle of annular channel region and 3D downstream of the cone's exit section are the optimum pressure-tapping methods. The relative error of discharge coefficient is within ±0.5%. This investigation will provide a theoretical and design basis for the development of new DP flow meters.

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Design of internal structures of conductance sensors for gas-water two-phase flow measurement

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AIP Conference Proceedings 2012年第1期1428卷 101-106页

作者： Xuelian Yu Feng Dong Chao Tan Can Wei Tianjin Key Laboratory of Process Measurement and Control School of Electrical Engineering and Automation Tianjin University Tianjin 300072 China No.92 Weijin Road China

Conductance sensor array is widely used in measuring two-phase flow parameters, in this paper we propose a new configuration of conductance sensors with six rectangular electrodes of same size from the pipe facing to an inner ring-type electrode and use it to measure gas cross-sectional-averaged water holdup value. The designed six rectangular electrodes are axially flush-mounted on the inside wall of an insulating duct. The geometry of six electrodes conductance sensor was determined with finite element numerical analysis. Sensor optimization of the electric field such as uniformity, spatial sensitivity is proposed. This configuration can improve measurement accuracy, through analyze sensitivity distribution, the role of soft field is discussed, and acquired the final size of the electrodes in the end. The simulation results were obtained from COMSOL Multiphysics finite element software.

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