Emulation And Modeling Of The Square Capacitance Field Sensitivity

Electrical Capacitance Tomography (ECT) is a new technology, but it needs to be designed as the square or the rectangular in many industrial applications, such as industrial boiler and circular fluid bed, i.e..The main object of the optimal capacitance sensor is to obtain the symmetrical capacitance field sensitivity. The ECT must base on the capacitance field sensitivity to design the array structure of the capacitance sensor. The ECT system must base on the prior knowledge of capacitance field sensitivity distribution of capacitance sensor when reconstructing image. So it is vital to get the capacitance field sensitivity distribution of capacitance sensor.At present, capacitance field sensitivity distribution can be obtained in two ways, i.e., experiment and finite element simulation. The former has many difficulties ensuring the degree of accuracy of measurement and simultaneously needs to do a lot of experiments, but, by using a computer, the latter not only makes the process of data simplified also gets more accurate response values in the distribution of given medium, which is the reason why this paper adopts the latter.The author analyses the operating principle of ECT and builds up the mathematical model of the capacitance and the component factor of multi-component. According to variation principle, it establishes the Finite Element Model (FEM) of the system by changing the finite boundary value problem of ECT into equivalence variation problem. On the basis of the FEM of the system, the paper builds the finite element model of the capacitance field sensitivity distribution. Electric charge method adopted in the course of evaluation has several advantages such as simplicity and quickness in calculating quantity of electric charge on an electrode and capacitance between two electrodes andenhances the real-time ability of ECT system obviously. The author programs the finite element software of capacitance field sensitivity, the compare of the simulated result with the static experimental result shows that the error of them is less than 0.9%, and then it proves the validity of the FEM of the ECT from different aspects. With FEM and qualitative analysis of effect of each structural parameter of the capacitance sensor on its capability, this paper optimizes the structural parameters of the capacitance sensor, and obviously improves its capability.The mathematical model of the capacitance and the component factor of multi-component flow shows we can build up the image of the multi-component flow section. The author programs the finite element software of capacitance field sensitivity according to its finite element mathematic model, then the numerical value can be got. The ultimate results are applied to the prototype of ECT system, ant it proves that the field sensitivity proposed in this paper is in accordance with the practice and obtains good results in the application.