Soot oxidation-induced fragmentation: Part 2: Experimental investigation of the mechanism of fragmentation

Temperature and oxygen effects on oxidation-induced fragmentation of soot particles

“…However, despite the novelty and possible impact on soot emission in combustion, oxidation-induced fragmentation has not been fully incorporated into soot models, with some exceptions. Recently, due to new studies conducted on a two-stage burner similar to Sarofim and Neoh's [27][28][29][30][31], and due to the increased number of details now possible in soot combustion models, oxidation-induced fragmentation can be taken into account [32][33][34].…”

“…The two-stage burner proposed by Sarofim and Neoh [26] and this group [27][28][29][30][31]35] isolates oxidation from formation, allowing more complex and hidden phenomena to be studied, such as oxidation-induced fragmentation. Further details of the two-stage burner can be found in previous experimental work [35].…”

“…Experimental investigations, mainly conducted on a two-stage burner, have shown that during the oxidation of soot particles in high-temperature environments, fragmentation of aggregates and even fragmentation of primary particles may occur [27,30,31]. The evolution of particle size distributions (PSDs) obtained with two-stage burner setup has constituted a benchmark for the modelers to approach the problem and the agreement of model predictions with results produced in the two-stage burner represents an achievement.…”

“…Oxidation by OH and O 2 are considered surface processes able to subtract carbon atoms from the particles. Oxidation-induced fragmentation of particles can occur if the oxidizing species penetrate the aggregates or even the particles and remove C atoms from a weak point causing the break-up of the large aggregates and particles into smaller aggregates and smaller particles [30,31].…”

“…The fragmentation of aggregates occurs if the carbonaceous material at the contact points of the primary particles is oxidized destroying the "bridges" holding together the primary particles. Recently, our group has shown that these "bridges" are more reactive as compared to the rest of particle surface [30,31].…”