The Three-dimensional Electrostatic Field Analysis And The Optimal Design Of Capacitive Sensor

The on-line detection of multiphase parameter plays an important part in the monitoring and control of production process,reliable operation, energy-saving, and emission reduction, etc. But the multiphase flow has characteristics of complicated flow and randomness in the flow process, which result the on-line measurement of parameter in the bottlenecks in the field of industry. Capacitive sensor is favored by scientific workers and industrial field deeply. Because it has advantages of no radiation, non-invasive, simple structure, low cost, large scope of application, fast response time, perfect safety, etc, which especially fit for the detection of multiphase flow parameter. According to the estimates, we can know that the capacitive transducer technique has a great prospect of application in the industrial measure control and even in the medical monitoring. But one of the main reasons which for hindering its practicality is that the sensitivity field characteristics and optional design problems of capacitance sensor.The subject is set in the detection of multiphase flow parameter, theoretically based on engineering electromagnetism and FEM, treating the large-scale finite element software ANSYS as the research platform. The primary research object is8-pole electrode array ECT sensor and spiral capacitive phase concentration transducer. This paper makes use of the research and analytical method on the simulation and experimental validation, thoroughly investigate the sensitivity characteristics and achieves the research aims of the structural parameter and performance optimizing design of capacitance sensor. The major work and results are as follows:(1) Summarize briefly the development application and existing problems of capacitance sensor. Analysis the superiority of the multiphase flow parameter during examines. Analysis the working principle of the sensor, founding mathematical models and optimization method selection of the sensor. (2) In view of the complicated characteristics of the detection field of capacitance sensor, examine the sensitivity characteristics thoroughly. By way of ANSYS software simulate3D electrostatic field. Aim at different sensors, analysis the influence of different parameters on the uniformity, sensitivity and other index factors.(3) According to the optimization design and different application purposes of capacitance sensor set the different optimized targets of8-pole sensor and spiral capacitance concentration sensor. By way of the computer simulation, we can get the optimal sensor structural parameter and improve the performance of sensor.(4) Under the condition of laboratory, we have a static experimental study on8-pole ECT sensor and spiral capacitance concentration sensor. The test results are consistent with the simulation calculation. Have measurements of sensitivity and uniformity of different sensors. The experiment results indicate that with ANSYS now, the performance index of sensor is better than before. The uniformity error of the spiral capacitance concentration sensor is less than4%, and the score of space image error is2.98578on the set of various flow patterns about the8-pole ECT sensor.