Chemical Mechanisms for Modelling HCCI with Gasoline and Diesel Oil Surrogates
Konferensbidrag (offentliggjort, men ej förlagsutgivet), 2005
Limited size chemical reaction mechanisms predicting ignition and combustion development of practical hydrocarbon fuels are necessary for multi-dimensional CFD modeling of the HCCI combustion mode in IC engines. In order to obtain accurate predictions within reasonable computational time, reduced mechanisms for gasoline and diesel oil surrogates have been constructed: 72 species, 313 reactions for diesel oil and 121 species, 614 reactions for gasoline. The mechanisms are based on sub-mechanisms developed for fuels constituent components, which are then reduced and optimized for engine applications. The optimization was performed using shock-tube and stirred reactor experimental data for individual components and the Chemkin-2 package software for computations and sensitivity analysis. The reduced mechanisms proved to be in a good agreement with the larger detailed mechanisms available in the literature as well as with relevant experimental data. Combined with the properties of liquid fuel, the diesel oil surrogate mechanism has been applied to reproduce spray ignition experiments in a constant volume vessel as well as for engine simulations, yielding a deeper understanding of the HCCI process.