An Integral Solution of the Aerosol Dynamic Equation Including Surface Growth Reactions

Abstract

A mathematical model examining the dynamic behavior of an aerosol undergoing simultaneous particle inception and coagulation or surface growth reactions and coagulation is presented. A bimodal configuration of the distribution function is used to formulate the problem when particle inception mechanisms arc present. Both modes of the distribution are assumed to be of a log-normal form with time varying properties. The model requires knowledge ofthe specific surface growth rate as a function of time, and is potentially applicable for studying aerosols where the surface growth reactions do not coexist with the particle inception mechanisms. The model is used to simulate the time evolution of a soot aerosol inside a flame environment and some important conclusions are drawn related to this problem.

Experimental study of the combustion dynamics of jet fuel droplets with additives in the absence of convection

“…Aggregates were collected from material that had been deposited on the support fiber. TEM images of JP8 soot aggregates appear to be connected by individual elements which have a spherical or near spherical shape, which is similar to the images of other studies [23]. Measurements of these individual aggregates averaged 60 nm with a large standard deviation of ± 20 nm.…”

“…Measurements of these individual aggregates averaged 60 nm with a large standard deviation of ± 20 nm. Dobbins and co-workers [23,29] reported precursor particles in a range of 10 to 40 nm in diameter for diffusion flames. Compared with this size, the aggregates measured in this paper would appear to be at a later stage of growth.…”

“…We investigated further this influence of +100 on soot by carrying out experiments in oxygen/helium 4 Soot formation is the transformation of precursor particles into opaque and agglomerated spherical monomers whose size ranges from 50 nm down to 10 nm [23]. Soot accumulation is defined here as the progressive build-up of aggregates between the droplet and the flame where they are trapped to form the soot shell [21].…”

Understanding the ignition mechanism of high-pressure spray flames

“…As the aggregate size grows with particle age, so do the primary-particle size and volume fraction [75,85,86] while the number density decreases or stays nearly constant [54,87,88]. The primaryparticle size and volume fraction will decrease during oxidation [85,86]. Although the volume fraction and size of mature soot particles depend on fuel type and combustion conditions, their morphology does not [89,90].…”

Numerical simulations of soot aggregation in premixed laminar flames

“…In most cases there is an initial phase of coalescent growth [11], where coagulation with small particles caused by high particle inception and rapid surface growth cause the particles to grow into near spherical "primary" particles. The coalescent regime is followed by particle aggregation, when the particles take on the form of fractal aggregates [15,14,20].…”