Investigation of Kinetics of Iso-Octane Ignition Under Scramjet Conditions (Postprint)
DAYTON UNIV OH DEPT OF MECHANICAL AND AEROSPACE ENGINEERING
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A single pulse reflected shock tube was used to investigate iso-octane ignition over the temperature range of 900-1400 K at a pressure of 1 atm. To account for the anticipated long ignition delay times at the lower temperatures, long shock tube dwell times 12 ms at lower temperature and near atmospheric pressure were achieved by using argon-helium mix as a driver gas. Chemical thermometer experiments were conducted to remove any uncertainties in determining post-reflected shock temperatures. The ignition delay data obtained in this study are in good agreement in the overlap region with the iso-octane ignition data from a previous shock tube study. However, the activation energy of iso-octane ignition obtained in this study in the lower temperature region 1300 K is significantly smaller 15 kcal vs. 40 kcal than that obtained in a previous higher temperature study. The deflagration may be responsible for lowering of activation energy under the conditions of this study. The AFRL mechanism showed a good agreement with measured ignition delays while a second mechanism Curran et al. showed poorer agreement.
- Physical Chemistry
- Fluid Mechanics
- Combustion and Ignition