Research And Design Of Three-dimensional ECT Capacitance Sensor

Electrical capacitance tomography(ECT) as an important field of the process tomography grows rapidly in recent years. For the principle of capacitance measurement, ECT has some advantages such as non-intrusion, safe and so on. Therefore, it is applied in many fields. Due to the addition of axial parameters, three-dimensional ECT system is more complex than the traditional ECT system. The performance of ECT sensor can affect the accuracy of image reconstruction. To improve the performance of sensor can improve the accuracy of the reconstructed image. Therefore, the optimal design of sensor is very significant, and the main content is as follows:To study the structural parameters of the three-dimensional ECT system and select 6 kinds of sensors with different structure to carry out group test. To select the factors that affect the performance of the three dimensional sensor, that is, the number of layers of the plate and the number of plates per layer. To select the optimal combination of the number of layers and the number of plates in each layer to meet the requirements of both axial and radial resolution. For the optimal combination of sensor model, to analyze and compare capacitance values of empty and full pipe. To change the thickness of shielding case, the value of plate angle and rotation angle between layers through experiment. To analyze the variation of capacitance with parameters, to draw the variation curves of the capacitance value and to give the reference range of the parameters of the three dimensional ECT sensor.To analyze the parameters that affect the performance of the sensor, the relationship between the parameters and the structure is nonlinear. The response surface method can be used to solve the problems such as calculation and stability.The change of function value of response surface is not too fast, so the second-order response function is adopted. With orthogonal test method, to selectthe test group of minimum objective function and substitute into the second order response function to obtain once and quadratic term coefficient. The structure parameters of sensor can be obtained through extreme value of response function.From the existing mature algorithms, to select the Landweber algorithm and LBP algorithm which has been applied to the reconstruction of 3D ECT image.To reconstruct the image of prototype model and analyze the results according to the error of the spatial image and the volume error of the 3D reconstruction image.The result is that, two algorithm's SIE and VE are decrseaed.