Non-Intrusive Measurement of Volume and Mass Using Electrical Capacitance Tomography

Volume 3 ◽  
2004 ◽  
Author(s):  
Andrew Hunt ◽  
John Pendleton ◽  
Malcolm Byars
Keyword(s):  
High Speed ◽  
Gas Flow ◽  
Mass Measurement ◽  
Large Individual ◽  
Electrical Capacitance Tomography ◽  
Electrical Capacitance ◽  
Recent Developments ◽  
Capacitance Tomography ◽  
Individual Particles ◽  
Individual Mass

Electrical capacitance tomography (ECT) has been used for some years to measure the concentration distribution within multiphase flows and processes. ECT is a relatively low resolution measurement, but it has many advantages, including being non-intrusive and fast. Recent developments of twin-plane systems have enabled measurements to be made of velocity as well as concentration. We have developed techniques to establish from these measurements the volume, mass and velocity of flow structures in two-component flows, and in particular the mass and velocity of large individual particles and groups of particles in solids/gas flow systems. Results are presented in the paper for simple gravity-drop flows of partly-filled plastic spheres, plastic beads, and also for the conveying of granular material in a pilot plant. We show that resolution of mass to within a few grams is possible on objects of individual mass of between 2g and 35g. We also show measurements of flow structure volumes in vertical solids conveying pipes of approximately 50mm diameter. General comparisons are made with high-speed video photography of some of the flows, and the in the case of gravity-drop flows the accuracy of the mass measurement is established using weighing.

A New Improved Data Acquisition System for Electrical Capacitance Tomography

2013 ◽  
Vol 756-759 ◽  
pp. 1527-1531
Author(s):  
Hui Zhang ◽  
Dan Ren ◽  
Li Ming Du
Keyword(s):  
Data Acquisition ◽  
Digital Signal Processor ◽  
High Speed ◽  
Phase Error ◽  
Data Acquisition System ◽  
Acquisition System ◽  
Electrical Capacitance Tomography ◽  
Electrical Capacitance ◽  
Logic Device ◽  
Capacitance Tomography

To improve the precision and speed of the system, a new 16-electrode electrical capacitance tomography (ECT) system based on DSP was designed. The measure system adopts 16 electrodes combined and floating capacitance sensor array, and with the phase located loop circuit to eliminate ECT systems additional phase error. The digital signal processor (DSP) is the core of data acquisition system, the computing and control unit includes a DSP (TMS320C5416) and a complex programmable logic device (CPLD). The communication module of the designed system is developed based on HPI parallel transmission technology, which can implement high-speed communication between ECT system and PC. Simulation results show that the sensitivity distribution was more uniform and the reconstructed images for objects were improved obviously by using 16-combined and floating electrodes sensor.

scholarly journals EVALUATION OF THE ELECTRICAL CAPACITANCE TOMOGRAPHY SYSTEM FOR MEASUREMENT USING 3D SENSOR

2019 ◽  
Vol 9 (4) ◽  
pp. 52-59
Author(s):  
Jacek Kryszyn ◽  
Damian Wanta ◽  
Waldemar T. Smolik
Keyword(s):  
Image Reconstruction ◽  
High Speed ◽  
Modular System ◽  
Capacitance Measurement ◽  
Electrical Capacitance Tomography ◽  
Electrical Capacitance ◽  
3D Image Reconstruction ◽  
Small Uncertainty ◽  
Small Change ◽  
Capacitance Tomography

Further tests of EVT4 data acquisition system for electrical capacitance tomography are presented. The modular system, which can have up to 32 channels with an individual analogue to digital converter, was designed to ensure small uncertainty of capacitance measurement at high speed of imaging. The system’s performance in the context of 3D imaging was experimentally verified. In particular, we show that the measurement of changes in capacitance due to a small change of an electric permittivity distribution for the most distant electrodes in a suitably designed 3D sensor is possible using our system. Cross-plane measurements together with the measurements for the pairs of most distant electrodes are essential for accurate reconstruction of 3D distributions. Due to sensitivity of capacitance measurements obtained in the hardware, the measurements for all electrode pairs can be used in the inverse problem – the system of equations can be extended. Although the numerical condition number of a matrix of such a system is high, image reconstruction is possible from the data obtained in our system. The results of 3D image reconstruction for simple test objects are shown.

scholarly journals A Finite Volume Method using a Quadtree Non-Uniform Structured Mesh for Modeling in Electrical Capacitance Tomography

2021 ◽  
Author(s):  
Damian Wanta ◽  
Waldemar Tomasz Smolik ◽  
Jacek Kryszyn ◽  
Przemysław Wróblewski ◽  
Mateusz Midura
Keyword(s):  
Finite Volume Method ◽  
Finite Volume ◽  
High Speed ◽  
Mesh Refinement ◽  
Electrical Capacitance Tomography ◽  
Electrical Capacitance ◽  
Assess Quality ◽  
Volume Method ◽  
Capacitance Tomography

AbstractAn electric field solver based on a finite volume method using refined structural mesh is proposed to implement a quadtree structure and estimate the electric flux in the mesh cell. Numerical experiments were carried out using uniform and non-uniform meshes to assess quality of numerical modeling. The proposed method of verification of the quality of numerical calculations based on circular symmetry of the electrical capacitance tomography (ECT) probe allows to assess the effectiveness of mesh refinement and to reduce the number of mesh elements. Experiments showed that even a moderate level of mesh refinement is sufficient to significantly reduce the simulation error that occurs in modeling of cylindrical probes. The reduced number of mesh elements and applied implementation of the quadtree ensures high speed of forward problem calculations.

scholarly journals Investigating the Characteristics of Two-Phase Flow Using Electrical Capacitance Tomography (ECT) for Three Pipe Orientations

Processes ◽  
2020 ◽  
Vol 8 (1) ◽  
pp. 51 ◽  
Author(s):  
Zeyad Almutairi ◽  
Fayez M. Al-Alweet ◽  
Yusif A. Alghamdi ◽  
Omar A. Almisned ◽  
Othman Y. Alothman
Keyword(s):  
High Speed ◽  
Two Phase Flow ◽  
Flow Patterns ◽  
Electrical Capacitance Tomography ◽  
Experimental Measurements ◽  
Phase Flow ◽  
Electrical Capacitance ◽  
Liquid Holdup ◽  
Two Phase ◽  
Capacitance Tomography

Experiments of gas–liquid flow in a circular pipe for horizontal and inclined positions (upward/downward) are reported. The characteristics of two-phase flow in terms of liquid holdup (ε(L)) and induced flow patterns are studied using three experimental techniques; time-averaged ε(L) from permittivity profiles using electrical capacitance tomography (ECT), instantaneous ε(L) using two fast-closing valves (TFCV), and high-speed camera images (HSCI) to capture/identify the formed flow patterns. Thus, this experimental setup enables the development of more well-defined flow patterns in gas–liquid two-phase flow and allows for multi-technique verification of the results. Taken from experimental measurements, a model is proposed to predict ε(L) for high and low situations. The correlations are a function of the hydrodynamic dimensionless quantities which provide hydrodynamic similarity. Regarding different pipe orientations, ε(L) predictions are comparable to ε(L) from experimental measurements with accepted accuracy: 88% of the predictions are within ±5–15% and 98% are below ±20%. The correlations also were validated by reported results and against correlations available in the literature and show higher prediction accuracy. It is confirmed that the kinematic similarity which is achieved by the gas–liquid velocity ratios and the inertial forces influence the flow pattern and the liquid holdup.

scholarly journals Liquid Film Thickness Estimation using Electrical Capacitance Tomography

2014 ◽  
Vol 14 (1) ◽  
pp. 8-15 ◽  
Author(s):  
Ziqiang Cui ◽  
Chengyi Yang ◽  
Benyuan Sun ◽  
Huaxiang Wang
Keyword(s):  
Film Thickness ◽  
Liquid Film ◽  
High Speed ◽  
Liquid Film Thickness ◽  
Electrical Capacitance Tomography ◽  
Electrical Capacitance ◽  
Oil Film ◽  
Thickness Estimation ◽  
Oil Flow ◽  
Capacitance Tomography

Abstract In air/oil lubrication systems, the flow parameters, e.g., flow pattern, liquid film thickness, and air/oil flow rate, are of great importance to the transportation efficiency. In most cases, the on-going two-phase flow is annular flow with the oil moving along the tube wall and the air travelling at high speed in the center. This usually results in the formation of a thin oil film, the thickness of which is a key parameter determining the efficiency of the lubrication system. As the oil film thickness of the on-going air/oil flow varies dynamically, there is actually no applicable method for a non-intrusive test. In this paper, the use of electrical capacitance tomography (ECT) to investigate the air/oil flow has been studied. Capacitance measurements are made from an externally mounted electrode array in a non-invasive and non-intrusive manner. Both average and distributed oil film thicknesses can be calculated from the reconstructed ECT images. Simulation and experimental results show that the ECT technique can provide satisfactory results of online oil film thickness estimation

scholarly journals Interface and permittivity simultaneous reconstruction in electrical capacitance tomography based on boundary and finite-elements coupling method

2016 ◽  
Vol 374 (2070) ◽  
pp. 20150333 ◽  
Author(s):  
Shangjie Ren ◽  
Feng Dong
Keyword(s):  
Finite Elements ◽  
High Speed ◽  
Descent Method ◽  
Coupling Method ◽  
Shielding Effect ◽  
Electrical Capacitance Tomography ◽  
Electrical Capacitance ◽  
Simultaneous Reconstruction ◽  
Capacitance Tomography ◽  
Deposit Layer

Electrical capacitance tomography (ECT) is a non-destructive detection technique for imaging the permittivity distributions inside an observed domain from the capacitances measurements on its boundary. Owing to its advantages of non-contact, non-radiation, high speed and low cost, ECT is promising in the measurements of many industrial or biological processes. However, in the practical industrial or biological systems, a deposit is normally seen in the inner wall of its pipe or vessel. As the actual region of interest (ROI) of ECT is surrounded by the deposit layer, the capacitance measurements become weakly sensitive to the permittivity perturbation occurring at the ROI. When there is a major permittivity difference between the deposit and the ROI, this kind of shielding effect is significant, and the permittivity reconstruction becomes challenging. To deal with the issue, an interface and permittivity simultaneous reconstruction approach is proposed. Both the permittivity at the ROI and the geometry of the deposit layer are recovered using the block coordinate descent method. The boundary and finite-elements coupling method is employed to improve the computational efficiency. The performance of the proposed method is evaluated with the simulation tests. This article is part of the themed issue ‘Supersensing through industrial process tomography’.

High-Pressure Gas-Oil Two-Phase Flow Visualisation Using Electrical Capacitance Tomography

Volume 1 ◽  
2004 ◽  
Author(s):  
Carlos Gamio ◽  
Juan Castro ◽  
Fabian Garcia-Nocetti ◽  
Luis Aguilar ◽  
Leonardo Rivera ◽  
...  
Keyword(s):  
Gas Flow ◽  
Oil And Gas ◽  
Invasive Technique ◽  
Flow Visualisation ◽  
Electrical Capacitance Tomography ◽  
Gas Oil ◽  
Electrical Capacitance ◽  
Two Phase ◽  
Test Loop ◽  
Capacitance Tomography

Electrical capacitance tomography (ECT) was used to image various two-phase gas-oil flows in a 3-inch pressurized test loop. ECT is a novel non-invasive technique for imaging mixtures of electrically non-conducting substances. One of its most promising applications is the visualization of gas-oil flows. This work presents a series imaging experiments using a pressure-resistant ECT sensor. Varying the oil and gas flow rates, different flow regimes were established in the test loop. ECT images were obtained for each case and compared with (a) the flow observed through a transparent section in the loop and (b) the prediction of the Taitel-Duckler flow map. The results confirm the suitability of ECT for imaging gas-oil flows.

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