Skeletal and reduced kinetic models for methane oxidation under engine-relevant conditions

Natural gas is a promising alternative fuel which can be used in internal combustion engines to reduce carbon emission. Therefore the combustion properties of methane, the major component of natural gas, have received great attention recently. This work aims to provide skeletal and reduced kinetic models for methane oxidation, which can be used for efficient simulations of methane combustion under engine-relevant conditions. The Foundational Fuel Chemistry Model (FFCM-1) developed at Stanford University served as the starting kinetic model for the reduction process. A 25 species skeletal model was firstly obtained by using sensitivity analysis and a 17 species reduced model was subsequently obtained through quasi-steady-state assumptions. The reduction procedure was performed within the parameter range of pressure from 1 to 120 atm, initial temperature for homogeneous ignition from 1000 to 2500 K, and equivalence ratio from 0.6 to 1.4, which includes the engine relevant conditions. Extensive validations of the present skeletal and reduced kinetic models were demonstrated through comparison with the original FFCM-1 model in the prediction of the homogeneous ignition, extinction and ignition in perfectly stirred reactor, premixed flame propagation and detonation properties. Very good agreement is achieved and thereby the original FFCM-1 model can be replaced by the present skeletal or reduced kinetic models in simulations of methane combustion.