Electric Potential Distribution of Electrical Capacitance Tomography System at the Centre of Pipe Based on Segmented Excitation

2013 ◽  
Vol 64 (5) ◽  
Author(s):  
Shahrulnizahani Mohammad Din ◽  
Ruzairi Abdul Rahim ◽  
Leow Pei Ling
Keyword(s):  
Electric Potential ◽  
Pipe Flow ◽  
Potential Distribution ◽  
Electrical Potential ◽  
Comsol Multiphysics ◽  
Electrical Capacitance Tomography ◽  
Electrical Capacitance ◽  
Tomography System ◽  
Resolution Problem ◽  
Capacitance Tomography

Electrical capacitance tomography (ECT) is one of the systems used to inspect closed pipe flow. This paper will present the proposed segmented excitation of electrodes with a focus on the low resolution problem.  Modelling of 8, 12 and 16 electrodes is done using COMSOL Multiphysics. The number of excitation electrodes is increased until half of the electrodes are excited at the same time. The electrical potential distribution is analyzed and the voltage value at the centre of the pipe is captured. The results show that there is improvement of electrical potential and voltage value in proportion to the number of electrodes excited at the same.

Electric Potential of Various 4-electrode Segmentation Excitation for Electrical Capacitance Tomography System

2014 ◽  
Vol 69 (8) ◽  
Author(s):  
Shahrulnizahani Mohammad Din ◽  
Aizat Azmi ◽  
Chee Pei Song ◽  
Ruzairi Abdul Rahim ◽  
Leow Pei Ling
Keyword(s):  
Electric Potential ◽  
Field Effect ◽  
Electrical Potential ◽  
Fast Response ◽  
Comsol Multiphysics ◽  
Electrical Capacitance Tomography ◽  
Electrical Capacitance ◽  
Tomography System ◽  
Capacitance Tomography

Electrical Capacitance Tomography (ECT) system is a non-intrusive method to detect variation of permittivity distribution in a closed pipe. ECT offers fast response, cheap and non-radiation system. However, it suffers from soft-field effect. One of the proposed solutions to overcome this problem is by applying segmentation excitation, which is to have more than one electrode excited at one time. This paper focuses on various segmentation excitations of 4-electrode combinations using COMSOL Multiphysics software. The electrical potential is recorded at the center of the pipe to study the strength of the electrical potential. The result indicates that 4-electrode adjacent configuration recorded 1.005 x 10-9V at the center of the pipe as compared to 0.838 x 10-9V for opposite configuration. This effect shows 16.6% difference in electrical potential at the center of the pipe.

Sensor Modeling For An Electrical Capacitance Tomography System Using Comsol Multiphysics

2012 ◽  
Author(s):  
Muhammad Afiq Zimam ◽  
Elmy Johana Mohamad ◽  
Ruzairi Abdul Rahim ◽  
Leow Pei Ling
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Comsol Multiphysics ◽  
Electrical Capacitance Tomography ◽  
Electrical Capacitance ◽  
Tomography System ◽  
Physical Sensors ◽  
Capacitance Tomography ◽  
Sensor Modeling ◽  
Element Method

Kerja penyelidikan ini membentangkan proses pembinaan model bagi Pengesan Kapasitan Elektrik Tomografi (ECT) menggunakan Perisian Kaedah Elemen Terhingga (Finite Element method–FEM) COMSOL Multiphysics. Meskipun pengesan fizikal adalah dalam bentuk tiga dimensi (3D) tetapi secara amnya sering dimodelkan secara kepingan/ keratan rentas dalam bentuk dua dimensi (2D). Projek ini menunjukkan pendekatan model dalam bentuk geometri 3D dan 2D, linear FEM menggunakan perisian COMSOL Multiphysics dibina adalah untuk mendapatkan nilai kapasitor di antara elektrod apabila medan elektrik dikenakan dan untuk melihat bagaimana pengagihan permittivity di dalam paip yang bertutup menerusi pengesan. Bayang–bayang yang direkacipta dan nilai–nilai diukur dikemukakan dalam bentuk paip yg kosong dan aliran anulus. Model ECT adalah mewakili perkakasan yang sedia ada, ECT mudah alih yang telah dibina oleh Kumpulan Penyelidikan PROTOM UTM. Kata kunci: Pengesan; model; ECT; COMSOL multiphysics This work presents the development process for modeling an ECT (Electrical Capacitance Tomography) sensor using FEM software package COMSOL Multiphysics. The physical sensors are 3D dimensional but it has been common to model the slice or the cross–section in 2D. This project shows the modeling approach for 2D and 3D geometries, the linear Finite Element method (FEM) using COMSOL Multiphysics is developed in order to obtain the capacitance between electrodes when an electric field is applied and to obtain the permittivity distribution inside the closed pipe from the sensor. Generated phantoms and measured values are presented for empty and annular pattern. Simulation is verified using phantoms inside the 16 electrode sensor. The ECT model is representative by existing hardware, Portable ECT, PROTOM Research Group UTM. Key words: Sensor; modeling; ECT; COMSOL multiphysics

ELECTRICAL POTENTIAL AND ELECTRICAL FIELD DISTRIBUTION OF SQUARE ELECTRICAL CAPACITANCE TOMOGRAPHY

2015 ◽  
Vol 77 (17) ◽  
Author(s):  
Mohammad Din ◽  
Leow Pei Ling ◽  
Ruzairi Abdul Rahim ◽  
Nur Adila Mohd Razali ◽  
Jaysuman Pusppanathan ◽  
...  
Keyword(s):  
Low Cost ◽  
Electrical Potential ◽  
Flow Distribution ◽  
Chemical Reactor ◽  
Fast Response ◽  
Electrical Capacitance Tomography ◽  
Electrical Capacitance ◽  
Electrical Tomography ◽  
Tomography System ◽  
Capacitance Tomography

Electrical Capacitance Tomography (ECT) system helps user to understand the flow distribution inside the close pipe by detecting the variation of permittivity distribution in the inspection area. Generally, most reported ECT systems are implemented to circular shape pipe only. However, square shape pipes are sometimes found in power industry and chemical reactor, therefore this paper is studying the electrical distribution of ECT system within a square pipe. ECT is able to provide fast response, low cost and non-radiation system but similar to all other electrical tomography system, ECT suffers from soft-field effect. This paper proposes segmentation excitation to overcome this problem. Segmentation excitation applies when more than one electrode excited at one time. This paper focuses Protocol 2 or 2-electrode excitation for 8-electrode square ECT system. The simulation was done by using COMSOL Multiphysics.  The images of the excitations are presented in this paper. The electrical potential is recorded at the center of the system to analyses the strength of the electrical potential. In addition for square ECT system, the corner configuration provides 3.40% higher electrical potential compared to side excitation configuration.

Electrical Capacitance Tomography (ECT): An Improved Sensitivity Distribution Using Two-Differential Excitation Technique

2015 ◽  
Vol 74 (1) ◽  
Author(s):  
Elmy Johana Mohamad ◽  
Hanis Liyana Mohmad Ameran ◽  
Ruzairi Abdul Rahim ◽  
Omar Md. Faizan Marwah
Keyword(s):  
Potential Distribution ◽  
Dielectric Material ◽  
Signal To Noise Ratio ◽  
Central Area ◽  
Voltage Source ◽  
Electrical Capacitance Tomography ◽  
Electrical Capacitance ◽  
Sensitivity Distribution ◽  
Differential Excitation ◽  
Capacitance Tomography

In this study, we propose the use of the two-differential potential excitation technique in an Electrical Capacitance Tomography (ECT) system to improve: (1) the non-uniform sensitivity distribution caused by the non-uniform potential distribution in the central area; and (2) the nonlinear relation between capacitance and material permittivity. A simulation of a 16-segmented ECT system is developed using COMSOL Multiphysics to observe the changes of the inter-electrodes capacitances and the permittivity of the dielectric material when two differential excitation potentials are injected. Generated phantoms and measured values are presented. An experiment using the real system is also carried out to verify the simulations results. By using this technique, it was shown that the relationship between the capacitances measured from inter-electrodes and the permittivity became more linear. In addition, potential distribution is increased in the central area indicating an increase in the sensitivity distribution in the central area. The use of this technique increases the level of detected signals and improves the SNR (signal-to-noise ratio) as compared to those achieved using standard single-voltage source methods.

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