Application of repro-modeling for the reduction of combustion mechanisms

Abstract

The basic problem of mechanism reduction methods is to find functional relationships between selectedstate variables (e.g., some concentrations and temperature) and their rates. However, this information is present during the simulations with the full chemical model. As a new application of the repro-modeling approach, information for rates is extracted from detailedchemical calculations and stored in the form of high-order multivariate, polynomials. For an efficient utilization of the polynomials, a computer program was written that rearranges them to the form of multivariate Horner equations. The repro-modeling method is an alternative to the application of the quasi-steady-state approximation (QSSA) and of the low-dimensional manifold method. Pros and cons of these three methods are discussed in detail considering the preparations required, the accuracy attainable, the yield in computer time, and the limitations of the techniques. Simulations of the combustion of wet CO using two-variable and three-variable repro-models were24,000 and 11,700 times faster, respectively, than the SENKIN calculation using the full model. These calculations represent the first use of repro-modeling for combustion mechanism reduction.