Laser spark ignition of two-phase monodisperse mixtures

Experimental measurements of the minimum ignition energy for two-phase reactive mixtures involving a liquid fuel (n-heptane, JP4), using a Q-switched Nd-YAG laser operating at 1064 nm, are reported in this study. Ignition energies were measured for many different mixtures. We find that the minimum incident energy level leading to ignition lies for both fuels between 16 and 30 mJ. We also point out the high uncertainties obtained for such studies, due to the limited number of realizations possible in practical measurements. While incident energies are obtained with a good precision, transmitted energies present considerable dispersions. For comparison purposes, it might be important to take into account these uncertainties.