Simulation And Study On 32-electrode Electrical Resistance Tomography System

Electrical Resistance Tomography (ERT) can infer the distribution of the conductivity by measuring the joint electric potential in the sensitivity field and then get the distribution of object field in the pipe or vessel, without destroying or interfering with the object field. It has a wide application prospect in two-phase flow measurement with the advantages of low cost and non-invasion etc.To improve the size discrimination ability of the electrical resistance tomography system and satisfy the two-phase or multiple phase measurement of different pipe sizes, especially large size, a new method of 32-electrode ERT system is put forward. The main achievements are as follows:(1) According to electromagnetic principle, math model of ERT system is built, analytic solutions of forward question of ERT system in situations of the uniform medium, discrete phase concentric and discrete phase eccentric distribution are obtained. Impedance model of the electrode arrays is established. It plays the guiding role for the design of the electrode arrays. Stimulation and measurement modes of ERT system and characteristics are analyzed, it provides basis for model selection.(2) Based on the MATLAB PDE, simulation research of the 32-electrode ERT system is accomplished and electric potential and field distributions under the condition of the adjacent and comparative mode in the sensitivity field are obtained. The influences of the flow pattern, electrode number and air bubble's position and size on the solution of the ERT system are stuied. Based on the simulation results, a new method of solving the ERT system is proposed.(3) With the finite element method, the meshing of sensitive field is realized and the finite equations are established and solved on the basis of VC++. Then the numerical potential solutions of all the meshing points in the sensitive field are obtained, and mutually verfied with the results simulated by MATLAB PDE. Therefore, the foundation for the follow-up image reconstruction research is eatablished.(4) The principles of image reconstruction, characteristic of usual algorithms are analyzed. The principle and application of LBP algorithm are emphatically optimized.