Improved Aerodynamic Particle Concentrator for Single Particle Aerosol Mass Spectrometry: A Simulation and Characterization Study

In order to improve the detection efficiency of single particle aerosol mass spectrometry(SPAMS) on low level particles in the environment, an improved aerodynamic particle concentrator(APC) was developed.Based on the CFD simulation software FLUENT and the principle of the virtual impactor to concentrate particles, the traditional critical orifice sampling structure was improved, and the critical orifice size was enlarged from 0.11 mm to 0.22 mm.In addition, an additional rotary pump is introduced to exhaust the excess gas, which enables SPAMS to separate the particles from the excess gas into sample gas under the stable vacuum system.This device enables SPAMS to separate particles from the excess gas under the stable vacuum system before they are transported to the mass spectrometry inlet.The results show that the simulation value of particle concentration ratio is in good agreement with the experimental value, and the sample flow rate is increased by 3.4 times.When the particle size is in the range of 0.2-5 μm, the concentration ratio of ambient air particles is about 3-8 times.The aerosol concentration sampling device can not only realize the particle concentration and injection, but also improve the injection capacity of SPAMS for coarse particles.