High-Resolution Transmission Electron Microscopy of Soot Particles in Diesel Spray Flame (Properties of Soot Sampled in Bio-Diesel Spray Flame)

Abstract

For better understanding of soot formation and oxidation processes in a bio-diesel spray flame, morphology, microstructure and size of soot particles directly sampled in a spray flame fuelled with soy-methyl ester were investigated using high-resolution transmission electron microscope (HRTEM). The soot samples were taken at different axial locations in the spray flame, 40, 50 and 70 mm from the injector nozzle, which correspond to soot formation, peak, and oxidation zones, respectively. The bio-diesel spray flame was achieved in a constant volume combustion chamber under a diesel-like high pressure and temperature condition (6.7 MPa, 1000 K). Density, diameter of primary particles and radius of gyration of soot aggregates directly sampled onto the TEM grids in the flame reached a peak at 50 mm from the injector nozzle and was lower or smaller at 40 and 70mm.