The Formulation of Surrogate Fuels to Emulate the Combustion Behavior of Real Jet Aviation Fuels

摘要

A methodology for the formulation of surrogate fuels is tested by experimental measurements of the detailed gas phase combustion phenomena of an n-dodecane, iso-octane, 1,3,5-trimethylbenzene, n-propylbenzene surrogate mixture. This mixture is predicted to share the same gas phase combustion properties of a target Jet-A fuel, through the sharing of derived cetane number, H:C molar ratio, threshold sooting index and average molecular weight combustion property targets, in addition to a prescribed commonality of chemically kinetic significant intermediate species groupings. 1) A variable pressure flow reactor is used to chart the chemical reactivity of a stoichiometric mixture of surrogate/O_2/N_2 at 12.5 atm and 500-1000 K, fixing the carbon content at 0.3%. 2) The high temperature chemical reactivity and chemical kinetic-molecular diffusion coupling of the surrogate fuel is evaluated by measurement of the strained extinction limit of diffusion flames. 3) The autoignition behavior of stoichiometric mixtures of surrogate fuel in air is measured with a shock tube at 666-1226 K at close to 20 atm and with a rapid compression machine at 645-714 K at compressed pressures of 21.7 atm and at 674-849 K at a compressed pressure of 6.9 atm. The similarity of these experimental results to those previously reported for the target real fuel is evaluated and discussed in the context of surrogate fuel formulation science.