CFD–PBM Simulation of Multiphase Flow Component Combustion Synthesized Nanoparticles Using QMOM and TEMOM

Abstract

: Flame synthesis is a major method for controllable nanoparticle preparation, which involves coupled turbulence, heat-mass transfer and particle dynamic behaviors. Numerical simulation is an effective means to reveal its internal mechanism. This work establishes a coupled CFD-PBM framework to investigate TiO₂ nanoparticle formation via thermal decomposition of titanium tetraisopropoxide (TTIP) in a reacting flow reactor. The Reynolds-averaged Navier–Stokes (RANS) equations combined with standard k– ε model are adop ted to solve gas flow, heat transfer and species transport in ANSYS Fluent. For particle population dynamics, two moment methods are applied: the built-in Quadrature Method of Moments (QMOM) is used for moment calculation and diagnostic analysis; the Taylor-expansion Method of Moments (TEMOM) is realized via four User -Defined Scalars (UDS) to achieve flexible moment closure. The model considers TTIP decomposition, TiO₂ nucleation, surface growth and Brownian coagulation. Simulation results identify key regions of particle formation and evolution, and compare the performance of QMOM and TEMOM. QMOM presents sharper moment peaks with high sensitivity to spatial variation, while TEMOM obtains smoother distribution, lower numerical dissipation and computational cost. The combined framework integrates the advantages of two methods, providing a reliable tool for mechanism analysis and parametric research of flame-synthesized nanoparticles.