An augmented reduced mechanism for methane oxidation with comprehensive global parametric validation

Using a computer algorithm for automatic generation of reduced chemistry, an augmented reduced mechanism, consisting of 16 species and 12 lumped reaction steps, has been developed for methane oxidation from GRI-Mech 1.2. Because the present mechanism consists of a larger number of non-steady-state intermediates than the conventional four- or five-step reduced mechanisms, it exhibits good to excellent performance in predicting a wide range of combustion phenomena under extensive thermodynamical parametric variations. Specifically, the phenomena tested include perfectly stirred reactor responses, autoignition and shock-tube ignition delay times, laminar flame propagation speeds, and ignition-extinction limits of counterflowing systems, whereas the thermodynamical parametric variations include those of temperature, pressure, and composition. It is recognized that, with the anticipated increase in computing capability in the foreseeable future, use of the present four- to five-step mechanisms will be unnecessarily limiting. Consequently, it is suggested that efforts should be expended toward development of augmented reduced mechanisms for more comprehensive description of combustion phenomena and for their potential implementation in the computational simulation of complex flows and systems.