10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
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Investigation of the Role of Charging on the Particle Growth during Combustion in Spray Flame Aerosol Reactor
SUKRANT DHAWAN, Girish Sharma, Pratim Biswas, Washington University in St Louis
Abstract Number: 304 Working Group: Materials Synthesis
Abstract The precise control of particle formation and growth in combustion processes is important for a wide range of applications and their environmental implications. In combustion systems, such as a flame aerosol reactor, a large number of ionized species are produced because of chemical and thermal ionization mechanisms (1) with concentrations as high as 1010 #/cm3. These highly concentrated ions collide with particles and the particles collide with each other and coagulate to form larger particles. These ion-particle interactions can significantly impact the particle formation and growth processes that eventually affect the properties of the synthesized particles. Therefore, it is crucial to study the impact of charging to better understand the particle evolution and growth in the combustion systems, and for precise control of the properties of flame synthesized particles. In this study, the aim is to investigate the role of charging on the particle growth. To achieve this, TiO2 nanoparticles were synthesized in the spray flame aerosol reactor using TTIP as precursor and the in-situ charge distribution characteristics of the synthesized particles were investigated using a tandem differential mobility analyzer coupled with a condensation particle counter. These measurements were conducted at different heights above the burner to obtain the particle size and charge distribution a function of their residence time. The experimental measurements were then coupled with the theoretical aerosol dynamic equation to predict particle growth dynamics. In the model, both ion–particle interactions (Fuchs' charging theory) and particle–particle interactions were taken into account to simulate simultaneous charging, and coagulation of particles (2). The effect of charge on particle growth was examined at different flame condition and precursor concentrations.
References: 1. Fialkov, A. B. (1997). Investigations on ions in flames. Progress in Energy and Combustion Science, 23(5-6), 399-528. 2. Wang, Y., Sharma, G., Koh, C., Kumar, V., Chakrabarty, R., & Biswas, P. (2017). Influence of flame-generated ions on the simultaneous charging and coagulation of nanoparticles during combustion. Aerosol Science Technology, 51, 833-844.