An experimental study has been performed on the ignition process of liquid fuel particles to obtain the fundamental data of spray combustion. The particles consisted of the center particle and ligands arranged in a geometric configuration. The number of ligands was defined as coordination number. The particles were set in a combustion chamber and the combustion chamber was filled with a propane-air mixture at atmospheric pressure. The propagating laminar flame was formed with the hot wire ignition and the particles were ignited by the flame. The results showed that in case of coordination number 3, the dimensionless ignition delay of the center particle decreased with a decrease in the dimensionless particle distance, and that in case of coordination number 4 and 6, the dimensionless ignition delay of the center particle had a minimum. The minimum was the smallest in case of coordination number 6. The smaller particle diameter had the larger dimensionless particle distance that showed the minimun dimensionless ignition delay.
