Autoignition characteristics of aircraft-type fuels

An investigation was conducted of the ignition delay characteristics of five liquid hydrocarbon fuels in air. The test apparatus developed permitted independent variation and control of temperature, pressure, air flow rate, and fuel/air ratio in order that the effects of each parameter could be investigated independently. All of the fuels tested behaved in a predictable manner, that is, ignition delay time decreased as temperature, pressure, and fuel/air ratio increased. The results for the different fuels tested (Jet-A, MP-4, No. 2 diesel, ERBS, and cetane) were directly comparable, since it can be shown that the fuel spray characteristics from the multiple conical tube injector are relatively insensitive to small changes in fuel properties (viscosity, surface tension, and density).