EFFECT OF GRAVITY IN DIFFERENTIAL MOBILITY ANALYSERS.A NEW METHOD TO DETERMINE THE DENSITY AND MASS OF AEROSOL PARTICLES

摘要

Abstract-Mobility analysers select particles according to their electrical mobility.In order to take into account the effect of gravity in these analysers,we introduce the settling velocity in equations governing the behaviour of particles.We deduce a new transfer function taking into account the effect of gravity .Based on these theoretical results,we developed a new application .By simulta-neously measuring the relaxation time and the electrical mobility of aerosols,we measure the mass of a latex particle(diameter between 0.1 and 2 um)with a radial flow differential mobility analyser known under the name SMEC.The agreement between the theoretical and the experi-mental values is good and the uncertainty less than 5% for latex particles with a diameter greater than 0.5 um 1998 Elsevier Science Ltd.All rights reserved