CHARGING AND COLLECTION OF SUBMICRON PARTICLES IN 2-STAGE PARALLEL-PLATE ELECTROSTATIC PRECIPITATORS

A well-defined two-stage ESP experiment was carried out in the submicr on particle size range. The experimental setup consisted of five compo nents: a clean wind tunnel, a submicron particle generation system, an aerosol sampling and transport system, a submicron particle number co ncentration measurement system, and a pilot-scale two-stage parallel-p late ESP. Experimental collection efficiency data were obtained with a GMD of 0.03-0.2 mu m and a GSD of about 1.67 for air velocities betwe en 1.9 and 4.1 m/s under the nominal operation condition of two-stage ESP. The experimental data were then compared with the results of a nu merical collection efficiency model which takes into consideration cha rging rate equations, particle equations of motion, and collection per formance models. The comparison showed good agreement. It was confirme d from the comparison that the partial charging regime, where a portio n of incoming particles is not charged, exists when the particle size range is below about 0.03 mu m. This partial charging effect causes a significant decrease in the ESP efficiency. (C) 1997 American Associat ion for Aerosol Research.