On the role of gas-phase and surface chemistry in the production of titania nanoparticles in turbulent flames

Control of Particle Morphology and Size in Vapor-Phase Synthesis of Titania, Silica and Alumina Nanoparticles

“…(Suyama and Kato, 1976;Yoon et al, 2003 Using Ti 5 O 6 C l8 , an intermediate on the transition to TiO 2 , as nucleus in place of TiO 2 monomer resulted in a considerably different particle size distribution in a flame synthesis of titania. (Mehta et al, 2013) At present, little data are available on the kinetics of producing the intermediate species and their physical properties including vapor pressure and surface tension that are required for nucleation calculation.…”

“…(Kammler and Pratsinis, 2000) In parallel with experimental studies on the effects of the operating variables, numerous modeling studies have been made on the basis of first principles. (Landgrebe and Pratsinis, 1990;Xiong and Pratsinis, 1993b;Pope and Howard, 1997;Lee et al, 2001;Nakaso et al, 2001;Park and Rogak, 2003;Morgan et al, 2006;Moniruzzaman and Park, 2006;Ji et al, 2007;West et al, 2009;Sander et al, 2009;Zaitone et al, 2009;Shekar et al, 2012b;Mehta et al, 2013). However, there remains more to be understood in reaction and nucleation kinetics, sintering, and fragmentation mechanisms until the technology is developed to the stage of designing reactors for mass production of non-aggregated spherical particles for titania, silica, and alumina.…”

Bivariate extensions of the Extended Quadrature Method of Moments (EQMOM) to describe coupled droplet evaporation and heat-up

“…Here, the multivariate NDF is described by conditioning the Dirac delta functions of the (x þ 1)-th internal coordinate on Dirac delta functions representing the distribution for the x-th internal coordinate. CQMOM was successfully applied to model TiO 2 Àdistributions (Mehta et al, 2013;Sung, 2013;Sung et al, 2014), bubbles in a stirred tank (Petitti, Vanni, Marchisio, Buffo, & Podenzani, 2013) and flash nanoprecipitation Cheng, Vigil, & Fox, 2010). However, with respect to spray modeling, CQMOM as proposed in Yuan and Fox (2011) is a classical QBMM approach, where the NDF is approximated by discontinuous Dirac delta functions.…”

Bivariate extension of the moment projection method for the particle population balance dynamics

“…With this method, the multivariate NDF is rewritten as a product of univariate marginal NDF and a conditional NDF, both of which can be represented with a set of weighted particles. CQMOM has been successfully applied to simulations for TiO2-distributions [40], flash nanoprecipitation [41] and soot formation [42]. However, similar to QMOM, CQMOM cannot handle the shrinkage or fragmentation problem.…”