| Abstrakt: |
Aerosol measurement is used in a variety of fields such as nanotechnology, materials science, pollution monitoring, air quality measurements, combustion and engine exhaust analysis, inhalation toxicology, and medical studies. One of the most prevalent methods for aerosol measurement is to use electrical mobility. An electrical mobility spectrometer (EMS) is used to measure aerosol particles size distribution ranging from 10 – 1000 nanometers, under the influence of an electric field. The accuracy of this distribution is influenced by flow conditions, the geometry of the EMS, the electric field, and the number of electrode rings. In this work, a multi-channel EMS is studied using computational fluid dynamics to numerically simulate the flow pattern, electric field and particle trajectories in the device. We found that neglecting the effect of the electric field on particles outside the sizing region generates an oversimplified model leading to high particle loss to the flow guide. In order to reduce the number of particle losses and obtaining a more realistic particle distribution we proposed a modification to the electrode electric potential which effectively reduces the particle loss. The applied modification has quintupled the number of particles which are classified by the EMS. |
