Effect of Channel Geometry on the Performance of an Electrostatic Precipitator: A Comparative Numerical Study

This study presents a numerical investigation of the influence of channel geometry on electrohydrodynamic (EHD) processes governing particle transport in electrostatic precipitators (ESPs). A conventional rectangular channel is compared with concave configurations using a coupled multi-physics model that accounts for gas flow, electric field distribution, ion transport, and particle migration across a wide particle-size range. The results show that geometric modification significantly alters ion transport and charge distribution within the ESP channel. Compared with the rectangular configuration, the concave profile enhances ion penetration and particle charging, leading to improved collection efficiency across the entire particle-size range. The improvement is particularly pronounced near the minimum-efficiency region for submicron particles. Specifically, near 0.1 μm, the collection efficiency increases from approximately 30% in the rectangular channel to approximately 50% for the higher-contraction concave configuration, representing an improvement of nearly 20 percentage points. A comparison with a Venturi-like contraction further shows that abrupt geometric contraction produces localized space-charge accumulation and reduces the effective charging region. In contrast, smooth concave shaping promotes a more distributed electrostatic interaction region, resulting in improved particle collection performance.