Numerical Study of Nanoparticle Formation Mechanism in process of Combustion Synthesis
Date Issued
2012
Date
2012
Author(s)
Cheng, Po-Tse
Abstract
In this study , a TiO2 Monodisperse Particle Formation model(MPF Model) which describes the chemical reaction process of every reactions in combustion synthesis of TiO2 has been built based on the Pratsinis study in the synthesis of ceramic powders. The particle dynamics equations to simulate the synthetic of TiO2 in the methane flame are derived according to Kruis model about the characteristics of aggregate particles. In this TiO2 MPF Model, chemical reaction, Brownian motion, sintering, Van der Waal interaction and diffusion had been considered and the spread of particles and aggregates are assumed to be monodisperse. The particle size and growth in the synthesis process are described by the number concentration of particles (N), total particle volume per mass (V) and total particle surface area per mass (A). Finally, the TiO2 combustion synthesis process is classified into five regions as the precursor vaporization zone、the particle formation zone、the particle collision zone、the coagulation and aggregation zone and the completed production zone on the basis of particles characteristic(N、V and A).When fixed the collection height as 2.5cm, the particle size (dp) increased from 40.9nm to 54.2nm as O2/N2 increased from 20/80 to 50/50.
Subjects
gas-phase combustion synthesis
particle kinetics
particles prediction
Type
thesis
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