The Design Of FE Analysis Software On ECT System

Electrical Capacitance Tomography (ECT) is a kind of Process Tomography (PT) based on capacitance sensor. ECT has the advantage of being non-intrusive, fast in response, simple in structure and low in cost. The electrostatic field inside an ECT sensor has complicated boundary shape and boundary condition; the distribution of medium is complicated, too. This kind of question has no analytical solution. So the Finite Element (FE) simulation is important to the research of ECT. The existing commercial FE simulating software is general-service, and their computing precision has been verified for a long time, but usually they are expensive and not easy to grasp. Furthermore, the commercially available packages are not flexible enough for ECT investigation. Some functions necessary to ECT investigation, for example, the calculation of field sensitivity, are shortage. Therefore, developing special FE simulating software for ECT system is necessary.In this paper, the composition, the working principle and the mathematical model of Electrical Capacitance Tomography System are described. All kinds of solution method of the electrostatic field are compared, and the Finite Element Method (FEM) is educed. Then the main function of the FE simulating software package designed by writer is introduced in detail when the main steps of FEM are discussed.The software package is developed in Visual C++ under the environment of Windows XP. It is special 2D and 3D FE analyzing software for ECT, including three functions: pretreatment, FE analyzing and after-treatment. The software package completes the modeling and showing using OpenGL, grid using open resource codes-tetgen and triangle, calculating using matcom mathematic library, GUI using Visual C++, so the software package is independence.The correctness of results calculated by our software package has been tested against some analytical results and against ANSYS when the same FE mesh was used. The software package provides the interface files for ANSYS, so the users can put the output files from the software package into ANSYS.Finally, the software package gets the capacitance and sensitivity by simulating some 2D models. The paper shows the imaging results that were got by the capacitance and sensitivity. The paper also compares the axial response of three different sensors.