Preignition and Autoignition Behavior of the Xylene Isomers
Abstract
The relative preignition and autoignition reactivity of the xylene isomers (o-, mand p-xylene, or 1,2-, 1,3-, and 1,4-dimethylbenzene) has been studied. The principal objectives were to determine the relative reactivity among the isomers and the key oxidation branching pathways. Preignition experiments were conducted in a pressurized flow reactor facility at 600-850 K temperatures, 8 atm pressure, and lean equivalence ratios. Online analysis of the data included carbon monoxide and carbon dioxide measurements using a nondispersive infrared analyzer and molecular oxygen measurements using an electrochemical oxygen cell. Offline analysis, for identification and quantification of intermediate species, was performed using gas chromatography with flame ionization detection and coupling to a mass spectrometer. Additional experiments were conducted in a single cylinder research engine. Neat o- and m-xylene were oxidized in the PFR under preignition conditions. They showed no reactivity, so mixtures of each isomer with n-dodecane were tested and compared, and intermediate species were identified. This data helped resolve a recent controversy regarding the relative reactivity of the xylene isomers. Additionally, a mixture of p-xylene / n-dodecane was studied. To study the autoignition of the xylenes, the isomers neat, in binary mixtures with n-decane, and in six-component JP-8 surrogates were tested in the single cylinder research engine. The experimental data were analyzed and compared to existing chemical kinetic models, and it was concluded that at lower temperatures (<850 K), the xylenes show similar reactivity, and at higher temperatures, o-xylene is the more reactive isomer. The data can be used for the improvement of xylene chemical kinetic models, and the conclusions from this study will aid in the selection of the appropriate xylene isomer for JP-8 surrogate fuels.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 2010
- Accession Number
- ADA532365
Entities
People
- Robert H. Natelson
Organizations
- Drexel University