Spray combustion has been utilized in the most of internal combustion engines (ICE). However, it involoves the fuel atomization, droplet evporation and chemical reactions so that the mechanism is difficult to understand. Thus, combustion behvaior of the isolated droplet has extensively investigated. In these days, not only an isolated droplet but also droplet pairs and groups have been explored to obtain a knowledge on the interference effects between droplets. In our laboratory, hydrocabon fuels especially focused. Contrary to alcohol fuels, they show cool-flame and two-stage ignition which has large influences on the ignition characteristics in ICE. By using a Michelson interferometer, cool-flame behavior of droplet pairs is being studied.

Fig. 1 Experimental setup for droplet ignition


Fig. 2 Ignition behavior of an n-decane droplet pair(0.3 MPa, 650 K)