10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
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Charge Size Distribution of Aerosol Nanoparticles Generated by Electrical Heating: Measurements and Theory
MARIAM , Manish Joshi, Arshad Khan, B.K. Sapra, Bhabha Atomic Research Centre, Mumbai
Abstract Number: 1206 Working Group: Aerosol Physics
Abstract Aerosol particles (natural and/or anthropogenic) are electrically charged, either because of the underlying formation mechanism or by their interactions with surrounding ionic environment. Knowledge of electrical behaviour of charged particles is applicable in several fields like drug delivery, electrostatic precipitators, residence time of aerosols etc. (Kwok et al., 2006; Pettersson et al., 2010). Type of aerosol particles as well as their generation method have a significant effect on the magnitude of the particle charge. This work focuses on estimation of charge size distribution (measurements and theoretical interpretation) of aerosols generated by electrical heating of nichrome wire using ELPI (Electrical Low Pressure Impactor). A laboratory made hot wire generator was used for generation of nanoparticle aerosols for this context (Khan et al. 2014). For steady conditions, charge per particle was found to be increasing from 0.009 to 1.305 for the size range of 9 to 230 nm (integral number concentration > 107 per cm3). Depending on temperature, thermionic emission and surface ionization are responsible mechanisms, which operate when a metal is electrically heated. For the temperature under glowing conditions, surface ionization is dominant phenomenon and thermionic emission (threshold at much high temperature) is improbable. Theoretical comparisons of current density and polarity at varying temperature were made with experimental findings.
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