Research On The Time Of Flight Of Aerosol Particles Based On Multiple-beam Field

Aerosol particles have a significant impact on human health, environmental pollution, and national life. The accurate measurement of physical and chemical parameters and properties of the aerosol particles have important research value and significance in environmental monitoring, air quality monitoring, human health, biomedical and national defense sectors. Based on time of flight measurement technique, the method of measuring particle time of flight is presented with multi-beam illumination field and researched experimentally. In this paper, the main work is as follows:1. The method of measuring time of flight with multi-beam is put forward by studying of dual-beam method to measure time of flight. Based on the theory of aerodynamic particle diameter and the relationship between aerodynamic particle diameter and the relative velocity, deduce double beam time of flight measurement principle and multi-beam time of flight measurement principle.2. According to the requirement of the measurement, the nozzle with sheath flow and gas path systems is designed, the development of an aerosol particle injection system is completed, the particle motion state is captured with high-speed cameras, and the performance of nozzle with sheath flow is tested; The particle velocity is calculated by CFD(computational fluid dynamics) software.3. Based on the principle of multi-beam measuring time of flight as well as multi-beam model, experimental system of the time of flight measurement of aerosol particles is set up, including double-beam interference system, aerosol particle injection system, scattered light reception system and signal acquisition and processing system.4. The time of flight with double-beam, triple-beam, multiple-beam which spacing is 83μm, 100μm, 118μm and 197μm is measured with the measurement system, and the results are discussed and analyzed. The preliminary research results show the method presented in this paper is feasible.