posted on 2023-11-30, 19:07authored byMing Yang, Shengqiang Lin, You Wu, Handong Liao, Bin Yang
The
ignition delay time (IDT) is a fundamental combustion property
of a premixed system under realistic engine operating conditions.
In this paper, a numerical investigation into the autoignition of
a total of nine jet fuel surrogates is conducted, and a definition
of “error function (E)” is introduced
to quantitatively analyze the agreement between calculated values
by surrogates and measured data of Jet A/JP-8. Besides, a sensitivity
analysis is carried out for IDT to reveal the dominant reactions of
autoignition behavior, and the sensitivity coefficient of a specific
reaction is obtained, as well as the similarity index for 36 surrogate
pairings. With a kinetic scheme from the CRECK modeling group, each
surrogate is observed to present a comparable E value,
indicating their similar capability to describe the autoignition characteristics
of jet fuel across a wide range of conditions. What is more, from
a similarity index perspective, it is also noticed that there is a
great deal of similarity between any two surrogates. A series of comparisons
on IDT sensitivity spectra between a pair of surrogates which have
similar chemical compositions are conducted at last. On the basis
of these results, a speculation is proposed that polyalkylated benzene
is more suitable than monoalkylated benzene as the representative
of aromatics in the jet fuel surrogate, and iso-alkane other than
cycloalkane ought to be a major consideration in addressing the development
of a surrogate fuel. Therefore, what we recommend is that a rational
jet fuel surrogate should be composed of n-alkane,
iso-alkane, and aromatics, and the selected representative components
for aromatics will be given to polyalkylated benzene, such as m-xylene and 1,2,4-trimethylbenzene.