HyChem model: Application to petroleum-derived jet fuels

In this work we introduce an unconventional approach to modeling the high-temperature combustion chemistry of multicomponent real fuels. The hybrid chemistry (HyChem) approach decouples fuel pyrolysis from the oxidation of fuel decomposition intermediates. The thermal decomposition and oxidative thermal decomposition processes are modeled by seven lumped reaction steps in which the stoichiometric and reaction rate coefficients may be derived from experiments. The oxidation process is described by detailed chemistry of foundational hydrocarbon fuels. We present results obtained for three petroleum-derived fuels: JP-8, Jet A and JP-5 as examples. The experimental observations show only a small number of intermediates are formed during thermal decomposition under pyrolysis and oxidative conditions, and support the hypothesis that the stoichiometric coefficients in the lumped reaction steps are not a strong function of temperature, pressure, or fuel-oxidizer composition, as we discussed in a companion paper. Modeling results demonstrate that HyChem models are capable of predicting a wide range of combustion properties, including ignition delay times, laminar flame speeds, and non-premixed flame extinction strain rates of all three fuels.