Characterization of electrostatic sensors for flow measurement of particulate solids in square-shaped pneumatic conveying pipelines

Theoretical analysis of an electrostatic sensor with square-shaped electrodes for installation on a pneumatic conveying pipeline is reported in this paper. In comparison with ring-shaped ones, the square-shaped electrodes are more difficult to analyze because of the four sharp corners. Based on a mathematical model of the electrostatic sensor, induced charge on the electrode and hence the induced current are derived. Sensitivity distribution and frequency response of the sensor are consequently identified. Additionally, effects of the geometric dimensions and attributes of charged particles on the characteristics of the sensor are investigated. Experimental work was performed on a purpose-built particle flow test rig in order to verify the modeling results. Suggestions on the improvement of the electrostatic sensor design are also given.