Boundary Layer Burning of Fuel Surfaces: The Soot Field

Previous investigations in this laboratory on the structure of diffusion flames formed over a liquid fuel surface with a parallel oxidizer flow have been completed with the identification of the soot field. To this purpose the standard laser light scattering-extinction technique used by a number of authors has been adopted. Measurements of fluorescence and UV absorption are also reported. According to present measurements the flame can be divided into three zones: the fluorescence zone, where polycyclic aromatic hydrocarbons (PAH) are formed, the soot zone and the combustion zone. Soot inception seems to occur close to the high temperature combustion zone, but present measuremenls of the number density of soot particles may also indicate that soot is generated at lower temperatures, within the fluorescence zone.