HIGH-PRESSURE OXIDATION OF LIQUID FUELS FROM LOW TO HIGH-TEMPERATURE .2. MIXTURES OF N-HEPTANE AND ISOOCTANE

The oxidation of mixtures of n-heptane and iso-octane in a high-pressu re jet-stirred reactor has been investigated experimentally in a wide range of conditions covering the low and high temperature oxidation re gimes (550-1150K, 10 atm, phi = 1). The cool flame and negative temper ature coefficient regimes were observed below 750K. Above 750K, the no rmal high temperature oxidation of both fuels was observed. Reactants, intermediates and final products have been measured providing a usefu l picture of n-heptane-iso-octane mixtures oxidation. Cyclic ethers re sulting from the low-temperature oxidation chemistry of n-heptane and iso-octane were identified. The evolution of their concentration as a function of RON have been measured. These results are interpreted in t erms of reaction mechanism. Tentative correlations between RON and CO, CO2 and C2H4 in the cool flame region and for the high temperature ox idation (normal combustion) are presented.