Numerical study of improving spatial sensitivity uniformity using elliptical electrodes in electrostatic inductive sensor

Abstract

Electrostatic charging of solid particles has significant impacts on the material bulk properties in powder handling processes. Reliable quantification of how the particles are charged in the powder in terms of charge levels and charge polarity in process requires both high sensitivity and spatial homogeneity of the sensor in the measurements. Classic ring inductive sensor faces a well-known trade-off: a wide electrode improves homogeneity but reduces temporal/axial resolution, while a narrow electrode preserves resolution but suffers from non-uniform sensitivity. This study introduces an elliptical inductive sensor as a geometry-based alternative to the ring. Using a cross-sectional sensitivity simulation model, an elliptical electrode sensor (major axis a = 10 mm, minor axis b = 6 mm) was compared with conventional ring electrodes using quantitative uniformity metrics. Results demonstrate that the elliptical electrode sensor geometry achieves near-homogeneous response (Uniformity Index, UI ≥ 0.9) for electrode axial width, W ≈ a, whereas the ring sensor requires the axial width on the order of the pipe diameter to reach comparable homogeneity. Under identical modelling conditions, the elliptical electrode sensor achieves greater uniformity and reduces centre–edge disparity compared to ring electrodes enabling balanced charge measurements with improved homogeneity and good resolution.