Chemical Kinetics Modeling Tools for Hydrocarbon Scramjet Propulsion System Design

Reliable design tools are of paramount importance to predict the combustion processes under supersonic conditions, as obtaining ground experimental data under these conditions is difficult and expensive. Combustion Science & Engineering, Inc. (CSE) proposes to develop a global approach for creating and implementing reduced chemical kinetic mechanisms for hydrocarbon fuels in the design process of scramjet propulsion for hypersonic flight. This approach will use a detailed CH2O/H2/O2 reaction sub-set to allow for accurate predictions of non-equilibrium phenomena such as ignition and extinction assuming break-down of the fuel molecule into CH2O and H2. The rate constant for the fuel decomposition step will be evaluated from available experimental data. The reduced mechanism will consist of 14 species and 44 reactions, irrespective of the type of fuel is used. This model has been successfully demonstrated for propane to predict ignition and extinction under subsonic conditions. In this project, this approach will be extended to hydrocarbon fuels including hypersonic fuels such as JP-7 to predict non-equilibrium combustion phenomenon under supersonic conditions. The reduced model will be validated and optimized against available experimental data in the literature. Then, the reduced kinetic mechanism coupled with mixing model will be implemented in various CFD codes to test the compatibility and convergence criteria under supersonic conditions.