Characterization of the Bidimensional Size and Charge Distribution of Sub- and Supermicrometer Particles in an Electrostatic Precipitator

We develop and implement an approach to directly invert two-dimensional size and charge distributions for particles exiting a wire-plate electrostatic precipitator (ESP). Combined instruments used in measurement and data inversion include both a tandem differential mobility analyzer (TDMA) system and a DMA combined with an aerodynamic particle spectrometer. The two-dimensional size and charge distribution hence provides information about the charge levels attained by particles in the ESP, which can reach 300 elementary charges for supermicrometer particles. The main mode of the charge distribution is well-fit by a Gaussian profile over the entire range of measured particle sizes. We find the average charge scales in a power-law manner with exponents between 1.29 to 1.39. We compare measured size and charge distributions, along with particle size-dependent penetrations to a 1D model accounting for unipolar ionization and electrophoretic deposition.