Lumped primary mechanism

LUMPING OF THE DETAILED PRIMARY MECHANISMS 5.1 - Lumped primary mechanism... 

Table 4 Lumped primary mechanism for the oxidation of an alkane propagation reactions. Units mol, cm, s, kJ.

Table 5 gives the propagation reactions (not including metatheses) of the lumped primary mechanism of the oxidation of n-pentane. It must be noted that this scheme only includes 4 free radicals instead of 24 for the detailed mechanism 3 pentyl radicals, 3 peroxy radicals, 9 hydroperoxypentyl radicals and 9 hydroperoxypentyl-peroxy radicals the dihydroperoxypentyl radicals have not been considered. 

Estimation of the fractional stoichiometric coefficients and of the kinetic parameters of the lumped primary mechanism... 

This mechanism contains the main generic reactions that can be found also in the detailed primary mechanisms for the oxidation of the alkanes at low temperatures (T < 750 K) in Chapter IX. It is also very similar to the reduced mechanisms obtained by the "lumping" of the detailed mechanisms. Its analysis therefore gives information about the structure of oxidation mechanisms, but also demonstrates the limits of this approach. 

The lumping of the propagation reactions of the detailed primary mechanism described in Figure 4 can be carried out by considering effectively only four lumped free radicals, parents of the initial alkane molecule RH, i.e. ... 

This computer program generates detailed primary mechanisms of oxidation and combustion reactions of alkanes and lumped secondary mechanisms of the primary products formed. It is interfaced with the KERGAS reaction database and the THERGAS, KINBEN and KINCOR computer programs. It produces reaction models (mechanisms, thermodynamic and kinetic data) which can be used directly in the CHEMKIN computer programs. 

Other examples of reduced hydrocarbon mechanisms developed via chemical lumping include a primary oxidation mechanism for iso-octane containing only five intermediate lumped radicals (Ranzi et al. 1997), lumped schemes for higher... 

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