Particle-diameter distributions of soot in laminar diffusion flames are sampled, rapidly quenched, and analyzed using the electron microscopy. They are measured together with the data of soot mass concentration, gas species concentration and temperature in the same flame.
The results obtained are as follows.
The forms of soot taken in the film becomes the monodispersive particle and chainlike clusters at all positions sampled in the flames. The curve of particle-diameter distributions forms the lognormal distribution. The value of standard deviation (lnσg) are estimated to be about 0.4-0.6 for the monodispersive particle diameter and volume-equivalent sphere diameter obtained from clusters, and 0.2 for non agglomerated soot particles. Particles number concentration in the agglomeration are decreased by the dilution of the fuel with N2gas.