Evaluation of the influence of thermodynamic data for propane and propene ignition delay times.

Larisa León, Elke Goos, Christian Klauer, Lars Seidel, Fabian Mauss, Thomas Zeuch

Abstract

The influence of thermodynamic data on auto ignition chemistry for propane and propene has been investigated. Thermodynamic data with high sensitivity on simulation results have been evaluated thoroughly. It was found that a small change in the heat of formation of C3H6 has high impact on calculated ignition delay times for propene and propane / oxygen mixtures. The new thermodynamic data was calculated through statistical methods from quantum chemical results of the benchmarked quantum chemical method G3B3. This resulted in a very small decrease of the standard heat of formation at 298 K of C3H6 from 20.574 kJ/mol to 19.973 kJ/mol, which resulted in a 36% increase in the calculated ignition delay times. Additionally the calculated heat of formation of C3H5 was 33.6 kJ/mol higher than in the previously used data set. This major change of the heat of formation of allyl results in a 91% increase in calculated ignition delay time for propene as fuel at 1440 K. Allyl (C 3H5) shows to be a sensitive specie to the change of the thermodynamic data on the ignition delay times. The differences established through the comparison of these quantities shows a positive influence on the prediction of the propene and propane ignition delay times.