MEASUREMENTS OF COLLECTION EFFICIENCY OF SINGLE, CHARGED DROPLETS SUSPENDED IN A STREAM OF SUBMICRON PARTICLES WITH AN ELECTRODYNAMIC BALANCE

An experimental system based on an electrodynamic balance has been developed and tested for measurements of collection efficiencies of single, stationary charged droplets in a stream of oppositely charged submicron droplets. A light scattering technique based on optical resonances has been used to obtain collector droplet size and size changes due to the deposition of droplets with high precision. The technique involves the application of Lorenz-Mie theory to high resolution experimental elastic scattering data obtained with a continuously tunable ring dye laser. The effects of collector size in the range 9-37 mum, aerosol particle size in the range 0.038-0.15 mum, collector charge varying from 3.2 x 10(-14) to 3.3 x 10(-13) C, and stream velocity ranging from 5.0 x 10(-3) to 6 x 10(-2) m s-1, on the collection efficiency have been studied. Results have been compared with a theoretical model for the collection efficiency in the presence of electrostatic forces. Experimental values of collection efficiency are found to be in good agreement with those predicted by the theory.