Research Of The Key Question Of Electrical Capacitance Tomography

Flow imaging is a new technique developed rapidly in recent years, which has great developmental potential and wide industrial application prospect. Having many distinct advantages such as low cost, wide application field, simple structure, non-invade and better safety, Electrical Capacitance Tomography (ECT) has being the most popular research direction and the main development in flow imaging technique. There is still a lot of work to be done before practical use of the technique.The object of this dissertation is on the research of 8-electrode Electrical Capacitance Tomography system. The topics studied are: modeling and analyze using Finite Element Method, analyse and computation of sensitivity field, optimal design of transducer, image reconstruction. The main problems researched in the dissertation and achievements are as follows: The dissertation explains the science background and the theoretical and actual meaning of the task. The progress and the problems of the flow imaging technique are briefly explained. The advantages of electrical capacitance tomography are discussed. The paper discusses the formation and operating principle of ECT, and builds up the definite mathematical model by detail theoretical analyse, and establishes the Finite Element Model (FEM) of the system by changing the finite boundary value problem of ECT into equivalence variation problem according to variation principle. On the basis of the FEM of the system, the paper builds the finite element model of the capacitance sensitivity field distribution and programs its finite element simulation software and proves the validity of the FEM of the ECT from different aspects. With the FEM and the qualitative analyse of the effect of each structural parameter of the capacitance transducer on its capability, this paper optimizes the structural parameters of the capacitance transducer, and obviously improves its capability. The compare of the simulated result with the static experimental result shows that the error of them is less than 0.9%. So the research result of this paper lays the foundation of the practical application of on-line ECT system for industrial process.