Promotion of the self-ignition of fuel-air mixtures with mechanoactivated Al (Mg)-MoO3 particles

The ignition delay times of heptane-air and diesel oil-air mixtures with and without additives of mechanoactivated Mg-MoO3, Al-MoO3, and Mg-fluoroplastic nanopowders are measured using a rapid-mixture-injection setup. At temperatures below a certain threshold value, the metal-MoO3 additives produce practically no effect on the ignition delay time, whereas at higher temperatures, these additives sharply reduce the ignition delay time, down to the resolution time of the experimental method. The promoting efficiency of the small heterogeneous additives tested is many times superior to that of the known homogeneous promoters. Magnesium-fluoroplastic additives are demonstrated to produce no promoting effect on the ignition of the fuel-air mixtures studied. The mechanism of the action of the heterogeneous additives on the gasphase self-ignition of fuels is discussed.