C4+ Surrogate Models for Thermophysical Properties of Aviation Kerosene RP‑3 at Supercritical Pressures

Due to the complexity of the chemical
compositions in aviation
kerosene, simplified surrogate models have gained significant attention
to effectively reproduce the thermophysical properties of aviation
kerosene. The available surrogate models usually adopt uniform representative
compositions with a fixed ratio. However, given that aviation kerosene
is an extremely complex mixture and associated with physicochemical
reactions in actual heating processes, such simple models generally
cannot accurately reproduce the thermophysical properties of aviation
kerosene in a wide range of temperatures and pressures. Therefore,
this work aims to develop accurate and independent surrogate models
named C4+ for various thermophysical properties of aviation kerosene
RP-3 at supercritical pressures. The thermophysical properties include
density, viscosity, constant-pressure heat capacity, and thermal conductivity.
The C4+ surrogate models are determined by using a carefully designed
genetic algorithm to minimize the relative deviations between the
calculated and experimental data of the corresponding properties based
on the previous C4 surrogate model. Especially, the effects of pyrolysis
and autoxidation reactions have been equivalently introduced to the
corrections of the surrogate models. Consequently, the prediction
of our surrogate models shows overall good agreement with the experimental
measurements and the highest accuracy among all simplified surrogate
models so far.