AAAR 34th Annual Conference
October 12 - October 16, 2015
Hyatt Regency
Minneapolis, Minnesota, USA
Abstract View
Bipolar Diffusion Charging Efficiencies of Particles Ranging from 100 to 900nm
HUADONG YANG, Meilu He, Suresh Dhaniyala, Clarkson University
Abstract Number: 367 Working Group: Instrumentation and Methods
Abstract Bipolar diffusion charging is commonly used with electrical mobility techniques for particle size distribution measurements. For accurate particle size distribution calculation, the charge distribution acquired by particles sent through these chargers must be known. While theoretical charge distributions for bipolar charging are well established, recent studies have shown that the charge distributions of particles smaller than 50 nm are a strong function of particle size, charger type and charger operating conditions. In this study, we experimentally examine the aerosol charge efficiencies of particles ranging from 100 to 900 nm. The charge distributions are determined using mobility classified particles sized by a downstream Ultra-High Sensitive Aerosol Spectrometer (UHSAS). This study only focuses on singly charged, doubly charged and uncharged Ammonium Sulfate particles. The influence of charger type, particle concentration, and aerosol flow rate on particle charging efficiency is studied. In measuring the charge fractions, particular care is taken to ensure accurate consideration of UHSAS counting efficiencies and DMA transfer functions. We will present a comparison of the obtained charge distribution results against those reported by other studies and that predicted by theory.