Research On The Development Of Skeletal Chemical Kinetic Models For Primary Reference Fuel And Gasoline Surrogate Fuel (TRF)

Due to the diversity of components of real fuels and the complexity of chemical kinetics, the computer resources demanded by the combination of computational fluid dynamics (CFD) and detailed chemical kinetics exceeds the currently available computational abilities. Therefore, it is necessary to model a fuel’s physical and chemical properties by choosing some represented components and reduce a detailed mechanism while maintain its good performance. In order to solve the contradiction between maintaining the ability and reducing the size of the mechianism, a practical methodology of developing a skeletal chemical kinetic model for surrogate fuels with multi-components is proposed by exploring a new approach, called as’semi-decoupling’. Based on the methodology, a new skeletal chemical kinetic model for gasoline surrogate fuels is developed and validated against various reactors, including HCCI engines, and operation conditions. Research work completed in this thesis is as the following.1. Recent advancement and achievements in the chemical kinetic models for primary reference fuel (PRF) and toluene reference fuel (TRF) is reviewed systematically and the methodology of reducing detailed mechanism is summarized. Problems in the current studies are identified and discussed.2. The weaknesses of existing skeletal chemical kinetic models are compared and analyzed. Considering the limitation of existing methodology of reducing detailed mechanisms, the theoretical background and basic idea of the ’semi-decoupling’ methodology is presented. Based on the methodology, a practical technique of developing a skeletal chemical kinetic model for surrogate fuels with multi-components is proposed and applied to the construction of a skeletal model of iso-octane. Three different ’core’ mechanisms are compared and analyzed to reveal their common characteristic. Consequently, the detailed and comprehensive mechianism of ’CO～C1’ is chosen as the ’core’.3. A new skeletal chemical kinetic model of iso-octane is developed by using the ’semi-decoupling’ methodology in view of the fact that iso-octane is the simplest gasoline surrogate. The model is validated against shock tube, jet-stirred reactor, flow reactor, laminar flame speed and3D-CFD engine. 4. Based on the achievement of developing the iso-octane skeletal model, new skeletal chemical kinetic models of n-heptane and PRF are developed by using the’semi-decoupling’ methodology as an extention of the iso-octane model. The models are validated against measurement data from ST, JSR, FR, LFS and3D-CFD engine.5. Base on the skeletal model of PRF, new skeletal chemical kinetic models of toluene and TRF are developed by using the ’semi-decoupling’ methodology. The model is validated against ST, JSR, FR and LFS.6. The new model is applied to two kinds of gasoline surrogate fuels with different components based on TRF and validated against the real gasoline fuels on auto-ignition and combustion characteristic in ST, LFS and3D-CFD engine. Good agreement between predictions and experiments are obtained.