Study On Flame Speed And Chemical Reaction Mechanism For Alternative Fuels Of Aviation Kerosene

Aviation kerosene is conventional fuel of the aircraft power plant. But thecomposition of kerosene is very complex, mainly including complex hydrocarbons suchas alkanes, cycloalkanes and aromatics, in addition of the differences for type, origin,productive life, which lead to the extreme difficult to the experimental and numericalresearch. At present, most researchers use the alternative fuels which are close to theactual nature of kerosene to carry out research.On the basis of the component analysis of RP-3kerosene, an alternative fuel modelcontaining molar ratio40%n-decane,42%n-dodecane,13%ethylcyclohexane,5%p-xylene was proposed. Through the analysis, it’s found that the alternative fuel modelis same as RP-3kerosene on the number of carbon atom and hydrogen atom,hydrocarbon ratio, molecular weight, calorific value, viscosity and density.A new counterflow twin-flame test system suitable for the large moleculeshydrocarbon liquid fuel was designed and built. Using this system, flame speeds ofn-decane, n-dodecane, ethylcyclohexane, p-xylene, toluene, RP-3kerosene andalternative fuels with air under different initial temperatures at standard atmosphericpressure were measured. The analysis of results shows alternative fuels have the similarflame speed as RP-3kerosene, which confirms the similarity of chemicalreaction characteristics of alternative fuel models and kerosene, and further justifies thereliability of alternative fuel model.Based on the experimental measurement results and a large number ofexperimental data available in literatures, the chemical reaction mechanisms ofn-decane, n-dodecane, ethylcyclohexane, p-xylene were developed respectively. Usingnew mechanisms, through simulation, flame speeds, ignition delay time and molefraction distributions of intermediate components in the flame were calculated. Bycomparison with the experimental data, it’s found that the four mechanisms canaccurately predict the combustion characteristics of four fuels.Through integration of four mechanisms, a mixing mechanism for RP-3kerosenewas proposed. The mechanism consists of168species and1089reactions, and its size isnot very large. By comparing the calculated results with the experimental flame speed of four components alternative fuels of RP-3kerosene with air, it’s found thatthe mechanism has good performance on simulation calculation. The Effects onflame speed were studied, including the component number and component ratios ofalternative fuels, the molecular structure of fuels.The dynamic analysis was carried outon the ignition characteristics and flame propagation characteristics of kerosene.