Automatic Chemistry Mechanism Reduction on Hydrocarbon Fuel Combustion

An automatic mechanism reduction program, ReaxRed for combustion of hydrocarbon fuels was introduced. Six mechanism reductions methods are implemented in this program and generation of reduced mechanisms well was verification of them can be carried out automatically with high efficiency. ReaxRed thus serves as a good computing tool for reduction of detailed mechanisms for combustion of hydrocarbon fuels. ReaxRed was applied to reduction of detailed mechanisms for a RP-3 aviation kerosene surrogate model with 257 species and 874 reactions, and for a gasoline mixed surrogate which consists of 1389 species and 5935 reactions, respectively. A skeletal mechanism containing 78 species and a global reduced mechanism with 61 species were achieved from the RP-3 surrogate model. Both the skeletal mechanism and the global reduced mechanism reproduces combustion characteristics of the detailed mechanism such as the ignition delay, extinction, and distribution of species concentration over a wide range of simulation conditions. Reliability of reduced mechanism is further verified through brute-force sensitivity analysis and rate-of-production analysis. A skeletal mechanism with 266 species from gasoline mixed surrogate model can recover simulated results on;ignition delay time of one-component, two-component as well as multicomponent mixtures in a wider range of conditions. Furthermore, combustion paths based on time-integrated element flux analysis for the four sing-component fuels in the surrogate model can also be reproduced by the skeletal mechanism. The result shows that the achieved skeletal mechanism retains detailed mechanism's hierarchical structure and globe information. Combustion process of gasoline can be analyzed systematically and more easily based on the obtained skeletal mechanism.