Aerospace Engineering Commons^™

The global chemical characters of complex chemical fuel mixtures are explicitly determined by evaluating the abundances of chemical functional groups present within it rather by applying molecular species composition. Statistical analyses on the relationships of each chemical functional group and the chemical property targets of the fuel are rigorously developed. The results demonstrate that the four CPTs currently used in surrogate formulation - H/C molar ratio, derived cetane number (DCN), average molecular weight (MW), and smoke point (SP) - effectively constrain the chemical function group distribution of the fuel, hence, the global combustion behaviors of pre-vaporized fuel/air mixtures. Emulating the …

A high pressure laminar flow reactor facility (HPLFR) was designed and constructed to serve as a platform for the experimental study of the gas phase chemistry of small molecule species. This facility accommodates pressures from slightly above atmospheric to ~30 atm, temperatures from ambient to ~1000 K, and plug flow residence times on the order of 100 milliseconds to 10 seconds. Quasi-steady state NOx plateau (QSSP) experiments were conducted in the newly-constructed HPLFR to determine rate coefficients for the reaction H+O2(+M)↔HO2(+M) (H.9.M) relative to the reasonably well-known rate coefficient for H+NO2↔OH+NO. Initial experiments for M = Ar and N2, for …

Over a broad range of conditions and experimental configurations, recent experimental work has shown quantitative similarities between the pre-vaporized combustion behaviors of iso-dodecane (iC12: 2,2,4,6,6-pentamethylheptane), iso-octane (iC8: 2,2,4-trimethylpentane), iso-cetane (iC16: 2,2,4,4,6,8,8-heptamethylnonane), and a 50/50 (molar) iC8/iC16 mixture. Such similarity – typically within experimental uncertainties – suggests that these fuels share a significant subset of combustion chemistry related to fuel destruction into nearly equal fluxes of iso-C4 fragments. This proposition is used to develop a compact (43 species) kinetic model to describe iC12 combustion by using detailed chemistry models for iC16 and iC8, since at present, no detailed iC12 oxidation model …

Computational combustor design and analysis demands combustion kinetic models that are sufficiently compact in species number so that they can be used in multi-dimensional reacting computational fluid dynamics (CFD) simulations. These models ideally predict dynamic global combustion behaviors and emissions as faithfully as detailed kinetic models, but with significantly lower computational costs than even “reduced” models. Another aspect of computational engine analysis is the need to predict combustion and emissions behaviors resulting from variations in fuel composition, which is likely to increase as alternative fuels are used displace/replace conventional petro-derived aviation kerosenes. Accordingly, this work discusses a general methodology for …

Rate coefficients for the reaction H+NO2 → OH+NO (R1) were determined over the

nominal temperature and pressure ranges of 737-882 K and 10-20 atm, respectively, from spatially

resolved measurements in two different flow reactor facilities: one laminar and one turbulent. The

title reaction is important in a variety of situations including NO↔NO2 interconversion in the

power extraction stage of gas turbines, exhaust gas recirculation (EGR)-affected ignition in

reciprocating engines, and for H atom titration in elementary gas phase kinetics experiments. This

work determines absolute values of k1 with reference to the relatively well known rate coefficients

for H+O2+M → HO2+M …