SYSTEMATIC REDUCTION OF CHEMICAL KINETIC MECHANISM FOR THE COMBUSTION OF DIFFERENT GASOLINE-ETHANOL BLENDS
Filipe Silva Cota1; Ramon Molina Vale1; Gustavo Hindi2
1 Federal University of Minas Gerais; 2 FCA - LATAM
doi:10.20906/CPS/CILAMCE2017-0593
Resumo
Ethanol in Brazil has been used in either blends with gasoline or pure since 1931, but gained more attention in 1975 with the "Pro-Alcool" program and later in 2003 with the introduction of the flex fuel vehicles. This has happened mainly to reduce the dependency on fossil fuels. On the other hand it presents other benefits, such as being a renewable fuel, better combustion characteristics and reduction in some pollutant's emissions. The accurate prediction of the combustion behavior in internal combustion engines, via numerical simulation, depends heavily on the kinetic data of the chemical components of fuels used under different operating conditions. The complete fuel mechanisms may contain hundreds of species and involve thousands of elementary chemical reactions, which require great computational effort to simulate the system, making it often impracticable for industrial applications, considering the time required. The use of reduced kinetic mechanisms, capable of reproducing the main characteristics of these fuels, considering only some specific species and reactions involved during combustion, is an interesting alternative to reduce the computational effort and the time spent during simulations. With regard to the consolidation of alternative fuels and the need of numerical simulations to predict the behavior of engines with specific combinations of blends of ethanol in gasoline, the present work aimed to create a reduced kinetic combustion mechanism capable of representing the behavior of gasoline containing a range of ethanol fractions from 0% to 100%v/v. This paper proposes the use of the directed relation graph method with sensitivity analysis (DRG-SA) as a tool, for the systematic reduction for detailed mechanisms, capable of generating the skeleton of a mechanism consisting of the lowest possible number of species and reactions. As a validation parameter, ignition delay time data obtained experimentally through shock tube analysis was used. The results were then compared to the numerical data ob
Palavras-chave: DRG-SA; Chemical kinetics mechanism reduction; Autoignition; Gasoline/Ethanol blend