Investigation of the Effects of Electrode Geometry on the Performance of CD Sensor with Radial Configuration.

Electrodes are basic components of CD (capacitively coupled contactless conductivity detection) sensors, and different electrode structures (the configuration pattern or the electrode geometry) can lead to different measurement results. In this work, the effects of electrode geometry of radial configuration on the measurement performance of CD sensors are investigated. Two geometrical parameters, the electrode length and the electrode angle, are considered. A FEM (finite element method) model based on the CD method is developed. With the FEM model, corresponding simulation results of conductivity measurement with different electrode geometry are obtained. Meanwhile, practical experiments of conductivity measurement are also conducted. According to the simulation results and experimental results, the optimal electrode geometry of the CD sensor with radial configuration is discussed and proposed. The recommended electrode length is 5-10 times of the pipe inner diameter and the recommended electrode angle is 120-160°.