Chemical ignition delay of candidate drop-in replacement jet fuels under fuel-lean conditions: A shock tube study

摘要: Abstract Ignition delay times were measured behind reflected shock waves under fuel lean, high pressures conditions for conventional (JP-8) and alternative jet fuels — Fischer-Tropsch (F-T), alcohol to (ATJ), direct sugar hydrocarbon (DSHC), four bio-jet a biodiesel-like fuel. The primary goal of this study was investigate the effect structure on ignition in order assess differences relative JP-8. To support effort, characteristics few hydrocarbons that are proposed as surrogate components also investigated: n-heptane, n-dodecane, m-xylene, n-dodecane/m-xylene blend (77%/23% by volume) 2,2,4,6,6-pentamethylheptane (iso-dodecane). Two single-pulse tubes (heated non-heated) used obtain current data set. Using argon diluent (93% volume), experimental covered pre-ignition temperature range approximately 980–1800 K at pressure 16 ± 0.8 atm an equivalence ratio 0.5. Experimental results show negligible between JP-8, F-T, DSHC, biodiesel, fuels. They very similar those iso-dodecane conditions. However, ATJ slightly longer higher temperatures, iso-dodecane. m-Xylene reported significantly than other tested identical Kinetic modeling light branching carbon chain length large n-paraffins do not alter because predominant reactions oxidation C1-C4 fragments. discernable slowing decomposition m-xylene occurs concentrations greater 50% (by mol.). Further testing is required understand behavior stoichiometric rich In addition, empirical correlation obtained global activation energy single paraffinic species their derived cetane numbers. This contributes recent efforts aimed provide relationships pre-vaporized, homogeneous combustion properties with existing indicators.