Soot characterization with laser-induced incandescence applied to a laminar premixed ethylene–air flame

Laser-induced incandescence (LII) has emerged as a promising non-invasive technique for measuring spatially and temporally resolved soot volume fraction and size. In this investigation we try to assess its performance in more detail by characterizing primary particle sizes using time-resolved LII and soot volume fractions by 2D LII. The experiments were performed at a fixed location in premixed ethylene/air flames burning on a sintered stainless-steel plug (McKenna) burner with varying values of the equivalence ratio for primary particle sizing and on the burner axis for concentration measurements. Maximum soot concentrations follow a power law behavior with equivalence ratio. The primary particle sizes obtained from LII decay curves are in good agreement with the values measured by other techniques and show a clear rise of particle size with equivalence ratio. The data analyzed with the help of a validated LII model will be useful for the further development of soot formation models.