Autoignition of propane-air mixtures behind reflected shock waves

Ignition times and autoignition modes for propane-air mixtures have been studied behind reflected shock waves. Experiments were performed over temperatures between 1000 and 1750 K, pressures between 2 and 20 atm, and equivalence ratios of phi = 0.5, 1.0, and 2.0. Ignition delay times were determined using pressure measurements, C, emission profiles, and luminosity measurements in the visible spectrum (380680 nm). Empirical correlations for ignition time for low temperature (1000-1300 K) and high temperature (1300-1800 K) ranges have been deduced from the experimental data. Different autoignition modes of the mixture (strong, transient, and weak) were identified by comparing velocities of reflected shock wave at different distances from the reflecting wall. (c) 2004 The Combustion Institute. Published by Elsevier Inc. All rights reserved.