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La Recherchev2


The electric charging of aerosols in high ionized atmosphere.



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F. Gensdarmes, D. Boulaud, A. Renoux, European aerosol conference 1999, 6-10 october 1999, Prague.


In case of accident within a nuclear pressurized water reactor, gamma irradiation could involve a high ionized atmosphere where the dose rate can reach 10 kGy/h. In such case the knowledge of the aerosol charge distribution is usefull for modelling aerosol transport and deposition in a close vessel. In a bipolar ionic atmosphere, the electrical charge distribution of an aerosol does not necessarily reach the Boltzmann equilibrium (Bricard and Pradel, 1966). Asymmetric charging could arise from the different diffusive properties between positive and negative ions. This asymmetry is represented by a parameter (X) defined by the positive to negative electrical conductivities ratio: X n n =µ+⋅+ µ−⋅− , where µ+ and µ- are respectively the positive and negative ion mobilities (m 2 /v/s), n+ and n- respectively the positive and negative ion concentrations (m -3 ). Several analytical expressions exist to determine the aerosol charge distribution according to ionic properties in the continuum regime (Gensdarmes et al. 1998). However there is very few experiments where both aerosol charge distribution and ionic properties are measured together. The aim of this work is to measure the asymmetry parameter and the resulting charge distribution on aerosol for differents ionization rate.