An Experimental and Modeling Study of the Combustion of Aromatic Surrogate Jet Fuel Components

The increase in air traffic has contributed to increase in emission of a number of volatile organic compounds (VOC’s) and particulate matter (soot). These emissions cause significant environmental damage and the inhalation of particulate matter is hazardous to human health. The key element to reducing emissions is in interpreting the combustion chemistry of aviation fuels. The coupling of detailed combustion chemical kinetics and computational fluid dynamics will provide insight into the effect of the fuel composition on pollutant formation. Jet fuels consist of several hundreds of chemical components and building a detailed chemical kinetic model for wide spread predictive use with computational fluid mechanics is probably impossible. An alternative approach is to choose surrogate fuel components that replicate the parent fuel in both physical and chemical characteristics and consequently can provide a more general and thereby practical fuel model. In the present work, the combustion chemistry of the aromatic surrogate fuel components of jet fuels, n-propylbenzene, 1,3,5-trimethylbenzene and m-xylene was investigated. This project was executed in three correlated approaches 1) Development of an experimental database: Experiments were conducted in the High Pressure Single Pulse Shock Tube on m-xylene, 1,3,5-trimethylbenzene and n-propylbenzene for pressures of 20 – 60 atm, for temperatures ranging from 900 – 1800 K and for different equivalence ratios ɸ = 0.5, 1, 2 and ∞. 2) Quantification of VOC’s and polycyclic aromatic hydrocarbons (PAHs): The products formed from the oxidation of these aromatic fuels were analyzed both qualitatively and quantitatively by using GC and GC/MS. Several volatile organic compounds (VOC’s) and polycyclic aromatic hydrocarbons (PAHs) were also measured in the products. Measurement of PAHs is important because chemical growth of PAHs leads to the formation of soot. 3) Development of a chemical kinetic models: The chemical kinetic models for the oxidation of n-propylbenzene, 1,3,5-trimethylbenzene and m-xylene were developed based on the experimental results obtained in steps 1 and 2. These models will be used to develop comprehensive chemical kinetic model for combustion of jet fuels.