Using In Situ Measurements to Experimentally Characterize TiO₂ Nanoparticle Synthesis in a Turbulent Isopropyl...

The objective of the present work is to show the potential of in situ measurements for the investigation of nanoparticles production in turbulent spray flames. This is achieved by considering multiple diagnostics to characterize the liquid break-up, the reactive flow and the particles production in a spray burner for TiO2 nanoparticle synthesis. The considered liquid fuel is a solution of isopropyl alcohol and titanium tetraisopropoxide (TTIP) precursor. Measurements show that shadowgraphy can be used to simultaneously localize spray and nanoparticles, light scattering allows to characterize the TiO2 nanoparticles distribution in the flame central plane, and spontaneous CH* and OH* chemiluminescences, as well as global light emission results, can be used to visualize the reactive flow patterns that may differ with and without injection of TTIP. Concerning the liquid, it is observed that it is localized in a small region close to the injector nozzle where it is dispersed by the oxygen flow resulting in droplets. The liquid droplets rapidly evaporate and TTIP is quasi-immediately converted to TiO2 nanoparticles. Finally, results show high interactions between nanoparticles and the turbulent eddies.