Reduced chemistry models construction

The challenge is to construct reduced chemistry models which are fast to evaluate, yet which still satisfy the error tolerance Eq. (13). One effective approach to this is the Adaptive Chemistry method (Schwer et al., 2003a, b), where different reduced chemistry models are used under different local reaction conditions. For example, in the 1—d steady premixed flame studied by Oluwole et al. (Oluwole et al., 2006), six different reduced chemistry models were used, and the full chemistry model only had to be used at about 20% of the grid points, Fig. 14. 

C. Constructing Reduced Chemistry Models Satisfying Error Bounds Over Ranges... 

Comparison of Eqs. (13) and (11) reveals that if one ran the CFD calculation to a computational to a convergence tolapprox = toltotai — , one could be certain that the resulting Fapprox would be a satisfactory solution of the full chemistry model, i.e. Eq. (11) would be satisfied. Methods for constructing reduced models guaranteed to satisfy Eq. (13) over a known range of conditions are discussed in detail in Section III.C below. The practical effectiveness of this overall error control approach, once one has an approximate source term fflapprox that satisfies Eq. (13) has recently been demonstrated for 1-d and 2-d steady laminar flame simulations. 

This approach makes it easier to satisfy Eq. (13) using small chemistry models, but it requires a method to easily obtain a set of reduced models appropriate for different conditions. In the next section, we present a method for constructing the various reduced models, and for identifying the range of reaction conditions where each should be used. 

A good understanding of the detailed chemistry of oxidant formation makes it possible to construct more compact chemical models. These generalized or lumped mechanism models reduce the number of individual chemical reactions by combining similar or sequential reactions and ig-... 

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