Sensor Modeling For An Electrical Capacitance Tomography System Using Comsol Multiphysics

Author(s):  
Muhammad Afiq Zimam ◽  
Elmy Johana Mohamad ◽  
Ruzairi Abdul Rahim ◽  
Leow Pei Ling

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

2012 ◽  
Vol 17 (4) ◽  
pp. 339-346 ◽  
Author(s):  
Paweł Kapusta ◽  
Michał Majchrowicz ◽  
Dominik Sankowski ◽  
Robert Banasiak

Abstract With the increasing complexity and scale of industrial processes their visualization is becoming increasingly important. Especially popular are non-invasive methods, which do not interfere directly with the process. One of them is the 3D Electrical Capacitance Tomography. It possesses however a serious flaw - in order to obtain a fast and accurate visualization requires application of computationally intensive algorithms. Especially non-linear reconstruction using Finite Element Method is a multistage, complex numerical task, requiring many linear algebra transformations on very large data sets. Such process, using traditional CPUs can take, depending on the used meshes, up to several hours. Consequently it is necessary to develop new solutions utilizing GPGPU (General Purpose Computations on Graphics Processing Units) techniques to accelerate the reconstruction algorithm. With the developed hybrid parallel computing architecture, based on sparse matrices, it is possible to perform tomographic calculations much faster using GPU and CPU simultaneously, both with Nvidia CUDA and OpenCL.


2013 ◽  
Vol 64 (5) ◽  
Author(s):  
Shahrulnizahani Mohammad Din ◽  
Ruzairi Abdul Rahim ◽  
Leow Pei Ling

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.


2014 ◽  
Vol 69 (8) ◽  
Author(s):  
Shahrulnizahani Mohammad Din ◽  
Aizat Azmi ◽  
Chee Pei Song ◽  
Ruzairi Abdul Rahim ◽  
Leow Pei Ling

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.


2016 ◽  
Vol 64 (1) ◽  
pp. 7-13 ◽  
Author(s):  
Onic Islam Shuvo ◽  
Md Naimul Islam

One of the major problems with Electrical Impedance Tomography (EIT) is the lack of spatial sensitivity within the measured volume. In this paper, sensitivity distribution of the tetrapolar impedance measurement system was visualized considering a cylindrical phantom consisting of homogeneous and inhomogeneous medium. Previously, sensitivity distribution was analysed analytically only for the homogeneous medium considering simple geometries and the distribution was found to be complex1,2. However, for the inhomogeneous volume conductors sensitivity analysis needs to be done using finite element method (FEM). In this paper, the results of sensitivity analysis based on finite element method using COMSOL Multiphysics simulation software are presented. A cylindrical non-uniform, inhomogeneous phantom, which mimics the human upper arm, was chosen to do the experiments by varying different parameters of interest. A successful method for controlling the region of interest was found where the sensitivity was maximum. Refining the finite element mesh size and introducing multifrequency input current (up to 1 MHz) this simulation method can be further improved.Dhaka Univ. J. Sci. 64(1): 7-13, 2016 (January)


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