Shock-tube study of the autoignition of n-heptane/toluene/air mixtures at intermediate temperatures and high pressures
- IVG, Universitaet Duisburg-Essen, D-47048 Duisburg (Germany)
- Shell Global Solutions, P.O. Box 1, Chester CH1 3SH (United Kingdom)
The ignition delay times of mixtures containing 35% n-heptane and 65% toluene by liquid volume at room temperature (i.e., 28% n-heptane/72% toluene by mole fraction) were determined in a high-pressure shock tube in the temperature range 620{<=} T{<=}1180 K at pressures of about 10, 30, and 50 bar and equivalence ratios, {phi}, of 0.3 and 1.0. The equation {tau}/{mu}s=9.8 x 10{sup -3} exp (15,680 K/T)(p/bar){sup -0.883} represents the data for {phi}=0.3 in the temperature range between 980 and 1200 K. At lower temperatures no ignition was found at 10 bar within the maximum test time of 15 ms, whereas for 50 bar, a reduced activation energy was observed. A pressure coefficient of -1.06 was found for the data with {phi}=1.0. No common equation for the data at {phi}=1.0 could be found analogous to that for {phi}=0.3 because the ignition delay times show no Arrhenius-like behavior. A comparison with ignition delay times of n-heptane/air and toluene/air for {phi}=1.0 and 30 bar shows that the values of the mixture of the two components are between the values of the single substances. Furthermore, the results confirm the negative temperature coefficient behavior found for the mixtures at 30 and 50 bar, similar to n-heptane/air. A comparison for the other pressure and equivalence ratio values of this study was not possible because of the lack of data for pure toluene. These experimental data have been used in the development of a chemical kinetics model for toluene/n-heptane mixtures as described in a companion paper. (author)
- OSTI ID:
- 20880638
- Journal Information:
- Combustion and Flame, Vol. 149, Issue 1-2; Other Information: Elsevier Ltd. All rights reserved; ISSN 0010-2180
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
HEPTANE
TOLUENE
PRESSURE RANGE MEGA PA 10-100
AIR
MIXTURES
EXPERIMENTAL DATA
AUTOIGNITION
TEMPERATURE RANGE 0400-1000 K
TEMPERATURE RANGE 1000-4000 K
SHOCK TUBES
TEMPERATURE DEPENDENCE
PRESSURE DEPENDENCE
ACTIVATION ENERGY
COMBUSTION KINETICS
PRESSURE RANGE MEGA PA 01-10