Combined Aerodynamic Size, Charge-to-Mass and Velocity Measurements of Aerosol Particles

摘要

A method is described for the determination of the aerodynamic size, charge-to-mass ratio and velocity of aerosol particles. The method involves the application of acoustic and/or alternating electric fields over the measuring volume of a laser doppler anemometer (LDA). The induced oscillating motion of an aerosol particle passing this measuring volume causes a frequency-modulated LDA signal. The characteristics of the oscillations and hence the aerodynamic size and charge-to-mass, as well as the velocity of the aerosol particle, can be determined after Fourier transformation of these signals. Experimental results regarding monodisperse particles show that not only histograms of aerodynamic sizes, charges and velocities but also e.g. turbulences and charges as a function of aerodynamic sizes can easily be determined with this method.