Formation and characteristics of Fe2O3 nano-particles in doped low pressure H2/O2/Ar flames

A new numerical approach for the simulation of the growth of inorganic nanoparticles

“…Figure 8 shows the result of the coagulation simulation. The evolution of the particle diameter over time is in good agreement with the experimental data of Janzen et al [21]. This result was obtained using a fractal dimension of 3.0, which implies that the particles sinter rapidly to spherical particles.…”

“…The illustrations and measurements show different trends, which seems odd especially when considering the excellent agreement that was obtained for the similar silica system. It is of note that the simulations carried out in [21] also over predict the particle diameters to a similar order of magnitude. This discrepancy is put down to a lack of kinetic data being available for the oxidation of FeCO 5 to Fe 2 O 3 along with subtleties that may lie in the coagulation.…”

“…Its kinetics have been estimated in order to make that particular reaction faster than the other two reactions. We justify making this assumption as the paper by Janzen and Roth [21] assumes instant formation of Fe 2 O 3 from Fe(CO) 5 at the start of the flame, whereas the paper by Giesen et al [22] gives a finite rate for the decomposition of Fe(CO) 5 . Since there is no further information about the rates, we chose to allow the oxidation part of the mechanism to not be the rate limiting step, hence its more rapid rate.…”

“…The simulated results agree excellently with the experimental measurements of Lindackers et al [18], predicting the increase in average particle mass with the initial concentration of SiH 4 . [21]. For this paper a simple skeletal mechanism was proposed.…”

“…Figures 7(a) and 7(b) show how the particle inception rate and temperature vary with time for this particular flame. Note that in [21] the total amount of Fe 2 O 3 that enters the system (the integral of figure 7(a) over time) is already in the system at time t = 0. Figure 8 shows the result of the coagulation simulation.…”