Theoretical Analysis of the Performance of the TSI Aerodynamic Particle Sizer The Effect of Density on Response

Abstract

The flow field in the TSI aerodynamic particle sizer (APS) has been modeled numerically and particle trajectories have been calculated. The effects of varying physical parameters such as beam location, beam separation, and nozzle separation were studied. Values of these parameters were determined for a particular APS by comparing the calculated particle transit times with measured ones for polystyrene latex and polyvinyl toluene aerosols. This configuration was used to determine the effect of particle density on APS response and to generate correction factors permitting actual aerodynamic diameter to be determined from indicated aerodynamic diameter when particle density is known. Sensitivity studies show that the calculated correction factors will apply to any TSI APS manufactured and operated within the manufacturer's specifications.