Impact of Reaction Chamber Geometry on the Particle-Residence-Time in Flame Spray Process

Production of functional nanoparticles and nanoscaled powders is a key process in several recent industrial applications. In this work, the flame process in nanoparticle production in sprays is analyzed. Specific focus is on the flow behavior, the temperature distribution, and the residence-time of particles in the hot (reactive) regions in a flame spray reactor that are analyzed by numerical simulations using computational fluid dynamics techniques. The role of the co-flowing gas rate provided to the flame spray reactor and its effects on the spray behavior, flame morphology, and particle properties in an enclosed atmosphere is highlighted. The influence of different operational conditions on the reactor temperature and temperature-residence-time distribution of gas and particles is investigated. It is found that providing a reduced co-flowing gas rate to the flame spray reactor favors the recirculation of hot gas, and, consequently increases the residence-time of particles in the high-temperature regions. The numerical results of particle diameter and gas-phase temperature are compared to some existing experimental data.