An experimental study of soot formation in C2H2/O2 flames at different C/O ratios in a closed chamber was carried out. The evolution temporal behavior and the volume fraction of soot particles were determined by laser extinction. It was found that total time for the soot formation phenomenon in flames from C2H2/O2 with C/O ratio > 0.75 or C2H2/O2/Ar with C/O ratio = 1.00 was around 3.0-4.0 ms after ignition. At almost the same time the excited radicals reached their maximum emission intensity and the gases under combustion reached their maximum pressure. The micrographs show compact and approximately spherical soot particles with diameters within 60-150 nm. However, soot aggregates are not compact and they present a netlike structure similar to that of an aerogel.
soot formation; closed chamber; combustion; laser extinction
