Title

Influence of Flame-Generated Ions on the Simultaneous Charging and Coagulation of Nanoparticles during Combustion

Abstract

Flames generate a large amount of chemically and thermally ionized species, which are involved in the growth dynamics of particles formed in flames. However, existing models predicting particle formation and growth do not consider particle charging, which may lead to bias in the calculated size distribution of particles. In this study, Fuchs' charging theory was coupled with a monodisperse particle growth model to study the simultaneous charging and coagulation of nanoparticles during combustion. In order to quantify the charging characteristics of nanoparticles, a high-resolution DMA was used to measure the mobilities of ions generated from a premixed flat flame operated at various conditions. The effect of temperature on ion—particle and particle—particle combination coefficients was further examined. The proposed model showed that the influence of charging on particle growth dynamics was more prominent when the ion concentration was comparable to or higher than the particle concentrations, a condition that may be encountered in flame synthesis and solid fuel-burning. Simulated results also showed that unipolar ion environments strongly suppressed the coagulation of particles. In the end, a simplified analysis of the relative importance of particle charging and coagulation was proposed by comparing the characteristic time scales of these two mechanisms.

Department(s)

Civil, Architectural and Environmental Engineering

Comments

This work is supported by the Solar Energy Research Institute for India and the United States (SERIIUS), funded jointly by the U.S. Department of Energy (Office of Science, Office of Basic Energy Sciences, and Energy Efficiency and Renewable Energy, Solar Energy Technology Program, under Subcontract DE-AC36-08GO28308 to the National Renewable Energy Laboratory, Golden, Colorado) and the Government of India, through the Department of Science and Technology under Subcontract IUSSTF/JCERDC-SERIIUS/2012.

Keywords and Phrases

Coagulation; Electric charge; Flame synthesis; Fuels; Ions; Nanoparticles; Characteristic time; Charging characteristics; Effect of temperature; Ion concentrations; Mono-disperse particles; Particle concentrations; Particle formation and growth; Simplified analysis; Combustion; Anion; Ion; Nanoparticle; Nitrate; Article; Chemical composition; Combustion; Dynamics; Environment; Flame; Ionization; Mass spectrometer; Mass spectrometry; Particle size; Priority journal; Temperature; Time

International Standard Serial Number (ISSN)

0278-6826; 1521-7388

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2017 American Association for Aerosol Research, All rights reserved.

Publication Date

01 Jul 2017

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