In this paper, a design of water-flow calibration facilities was proposed which was based on static mass method, static volume method and master meter method. Taking the water-flow calibration facility of Tianjin Univ...
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In this paper, a design of water-flow calibration facilities was proposed which was based on static mass method, static volume method and master meter method. Taking the water-flow calibration facility of Tianjin University Flow Laboratory for an example, this paper specified the experiment pipeline design, buoyancy and density correction, control system design, and other key issues. At last an uncertainty analysis of the facility was provided, and the experiment data showed the combined standard uncertainty of this facility was 0.0243% used static mass method and 0.0559% used master meter method.
In this paper, a gas flow calibration facility by master meter method is developed. The paper deals with the design methods and working principle. The simulation of the confluence tube is analyzed. The pressure loss o...
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ISBN:
(纸本)9781612844589
In this paper, a gas flow calibration facility by master meter method is developed. The paper deals with the design methods and working principle. The simulation of the confluence tube is analyzed. The pressure loss of pipe is calculated and the selection of the blower is analyzed. And then the distribution of the facility uncertainty is calculated. The uncertainty is better than 1% in the total flow range, and it is better than 0.5% at the fixed flow points.
The description for rising bubble is important for the study of principle of the Gas/liquid two-phase flow. As to the rising bubble, reconstruction the shape of the bubble can make a strong foundation for further desc...
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The description for rising bubble is important for the study of principle of the Gas/liquid two-phase flow. As to the rising bubble, reconstruction the shape of the bubble can make a strong foundation for further description. The bubble images were collected with two cameras; the images were preprocessed using digital images processing methods; parameters of the simulated ellipse were extracted with Hough transformation; and bubble simulated ellipsoid model were reconstructed based on these extracted parameters.
Electromagnetic tomography has potential value in process measurement. The frontier of electromagnetic tomography system is the sensor array. Owing to the excited signal acting on the sensor array directly, the excite...
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Electromagnetic tomography has potential value in process measurement. The frontier of electromagnetic tomography system is the sensor array. Owing to the excited signal acting on the sensor array directly, the excited strategy and the frequency and amplitude of the signal affect the quality of the information that the detected coil acquired from the object space. Furthermore, it would affect the accuracy of the information post extracted from the object field. To improve the sensitivity of the sensor array on the changes of the object field distribution, upgrade the sensitivity and accuracy of the system and guarantee high precision and high stability of the experimental data, use the finite element simulation software COMSOL Multiphysics to analyze the excited strategy and the characteristic of the excitation frequency of electromagnetic tomography. Establish the foundation in optimal using of electromagnetic tomography system.
Gas-solid two-phase flow is complicated and random, gas-solid two-phase flow standard facility is a very important method for the study of gas-solid two-phase flow problem. As to the design requirements of standard fa...
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ISBN:
(纸本)9781424494361
Gas-solid two-phase flow is complicated and random, gas-solid two-phase flow standard facility is a very important method for the study of gas-solid two-phase flow problem. As to the design requirements of standard facility, a gas-solid two-phase flow standard facility used to calibratio electrostatic sensor is designed.
In this paper, a continuous, time varying adaptive controller is developed for an underactuated quadrotor unmanned aerial vehicle (UAV). The vehicle's dynamic model is subject to uncertainties associated with mass...
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In this paper, a continuous, time varying adaptive controller is developed for an underactuated quadrotor unmanned aerial vehicle (UAV). The vehicle's dynamic model is subject to uncertainties associated with mass, inertia matrix, and aerodynamic damping coefficients. A Lyapunov based approach is utilized to ensure that position and yaw rotation tracking errors are ultimately driven to a neighborhood about zero that can be made arbitrary small. Simulation results are included to illustrate the performance of the control strategy.
A kind of measurement called “step” measurement method based on segmented capacitance electrodes is proposed in this paper. The “step” measurement method is implemented through increasing and reducing the width by...
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A kind of measurement called “step” measurement method based on segmented capacitance electrodes is proposed in this paper. The “step” measurement method is implemented through increasing and reducing the width by increasingly involving more the capacitance electrodes towards different axis directions. By this kind of measurement, the information of the flow both locally and globally can be acquired. The capacitance electrode model and the measurement method are presented in details. Based the simulations using finite element method, the relative capacitance differences are calculated. The gas-liquid cross-sectional phase distribution (annular flow, stratified flow, bubble flow) are identified. Besides, the relation between the mean relative capacitance differences and the level of the water of stratified flow is nearly linear. The “step” measurement data contains a lot of information of the flow, and further work will focus on the feature extraction method of “step” measurement data.
This paper introduces a new-type turbine flow meter. The concept is to apply magnetic suspension bearing to reform turbine flow meter. Beginning with the structure and working principle of magnetic suspension bearing,...
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This paper introduces a new-type turbine flow meter. The concept is to apply magnetic suspension bearing to reform turbine flow meter. Beginning with the structure and working principle of magnetic suspension bearing, the magnet suspension bearing is compared with the common bearing in their differences and characteristics. To draw a conclusion from the comparison that the turbine flow meter based on magnetic suspension bearings superiors to the one with common bearings, and the problems in the application of magnetic suspension bearing are introduced at the same time. Numerous experiments show that the range of measurement can be largely widened and the working life span of turbine flow meters also can be extended with magnetic suspension bearings.
Based on the analysis of signal of the piezoelectric detector, the relationship between natural frequency of the detector and vortex signal is discovered. Through the modal analysis of the piezoelectric detector's...
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Based on the analysis of signal of the piezoelectric detector, the relationship between natural frequency of the detector and vortex signal is discovered. Through the modal analysis of the piezoelectric detector's structure based on ANSYS, the relationship between the natural frequency and the detector's structure has been studied. Then by modifying the piezoelectric detector's structure and the low-pass filters' parameters, the measurement problem of high-frequency vortex signal has been solved.
Based on a higher raster angular displacement sensor, a fully-automatic higher precise apparatus for angular calibration is described. By using a higher resolution stepping motor, both of the two types of sensors, the...
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ISBN:
(纸本)9781612844589
Based on a higher raster angular displacement sensor, a fully-automatic higher precise apparatus for angular calibration is described. By using a higher resolution stepping motor, both of the two types of sensors, the standard raster sensor and the corrected sensor which are fixed in the same axial, can rotate coaxially at the same step. Meanwhile, the related software application platform is developed, which is being used for angular calibration and angular detecting. The output signals from the standard and corrected sensors can be transmitted to a host computer via one COM port. Take a kind of smart angular displacement sensor for calibration example, its angular displacement mathematic model embedded in MCU can be corrected by using this apparatus with higher accuracy so that the technique specification, like basic errors and linearity error can be improved greatly. For the four capacitive angular displacement sensors, their calibrating results sensors show that the averaged basic errors are 0.19%, 0.16%, 0.12% 0.15% respectively and the maximum is 0.62%, and the averaged linearity errors are 0.15% 0.12% 0.10% 0.14% respectively, and the maximum is 0.58% The accuracy of 1.0 level of this capacitive angular displacement sensor can be obtained.
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