Electrohydrodynamics of spiked electrode electrostatic precipitators

Abstract

The present electrode configuration and arrangement of the electrostatic precipitator (ESP) have been determined, based on experimental data from the laboratory scale ESP and operational experiences of the full-scale ESPs. However, there is a limitation to determine the optimal electrode design. As an alternate approach, the numerical simulation was investigated. A two-dimensional electrohydrodynamic (EHD) simulation for the wire electrode in the duct geometry was first carried out. Then, the experimental study and operational results of a full-scale ESP on the voltage–current characteristics were investigated. An applicable simulation model of electrical characteristics for the full-scale ESP was developed. Next, three-dimensional EHD simulation was carried out in order to understand the flow distribution for the typical industrial ESP geometry i.e. the spiked-type discharge electrode and convex–concave-type collecting electrode, in which the primary flow becomes three-dimensional due to ionic wind. The three-dimensional EHD simulation shows that the flow interaction due to ionic wind takes place at every spiked electrode region and a zig–zag motion is formed in the direction of the primary flow. The magnitude of the flow interaction is described by using dimensionless EHD number ( N EHD). The flow interaction in the typical ESP is not significantly large because the N EHD of the full-scale ESP is usually less than 1.0.