IN-SITU COMBINED SMALL- AND WIDE-ANGLE X-RAY SCATTERING FOR THE STUDY OF NANOPARTICLE DYNAMICS IN AN ETHYLENE DIFFUSION FLAME STABILIZED BY A METAL PLATE

Combined small- and wide-angle X-ray scattering techniques were used to study the dynamics of nanoparticle formation in-situ in an ethylene diffusion flame closely below a stabilizing and cooling metal plate on which particles condensed. The detectors allowed continuous monitoring of scattering intensities with a high dynamic range. The formation of species in the gas phase and during transfer into the condensed phase was studied as the temperature inside the flame decreased. Measurements were performed at two different heights above the burner monitoring X-ray scattering intensities and temperatures at the burner surface, at medium flame height and at the cooling plate. Strong changes were observed in the scattering properties as the temperatures decreased with time. The SAXS results show that a large number of particles between 1 and 10 nanometers are produced as the local temperature is decreased. The results have important implications on combustion control and the release of small nanoparticles.