Ignition Delays for Iso - octane: Measurement Using a Rapid Compression Machine and Prediction Using a Reduced Chemical Kinetic Model
Ignition delays were measured for iso-octane using a rapid compression machine at an equivalence ratio of 1, initial pressure of 300 Torr, and post-compression oxygen density of [O2]Vo=1.0, where Vo is 22,400 cm3/mole. The post-compression temperature were varied by changing specific heat ratio of mixture: this was done by blending different inert gases, i.e., CO2, N2, and Ar. Negative temperature coefficient region was observed between 750 K and 850 K. Two-stage ignition delay characteristic was observed below 830 K. Overall experimental results were found to be in good qualitative agreement with those by Shell's Thornton Research Center. The ignition delays predicted by MIT 19 reaction reduced chemical kinetic model were compared with those from the current experiment. In the model calculation, the measured pressure was fed into the model to calculate the core temperature before there is appreciable heat release due to chemical reaction.