On the Formation of Nitrogen Oxides During the Combustion of ...

A.1 Global Kinetics
2500
K
Spatial coordinate x
2000
Temperature T
1500
1000
Single-step mechanism
500
Two-step mechanism
Quasi-global mechanism
Detailed mechanism
0
0.000 0.004 0.008 0.012 0.016 0.020 m
Figure A.1: Temperature Profile of a Laminar Premixed Flame for Reaction Mechanisms
with Different Degrees of Abstraction. n-Decane is burned at stoichiometric conditions
(φ= 1.0). The inlet temperature is T = 500K at a pressure of 1.0bar.
With respect to liquid-fueled gas turbines, Lefebvre [243] points out that
chemical reaction rates vary only slightly between the various hydrocarbon
fractions of the fuel. This is due to only marginal differences in adiabatic flame
temperature of the particular fuels, on the one hand, and extensive pyrolysis
of all fuel fractions before entering the true reaction zone, on the other hand.
The major pyrolysis products are CH 4 , other 1-2 carbon atom hydrocarbons,
and H 2 . Consequently, the reactant composition in the reaction zone is virtually
independent of the parent fuel. Duterque et al. [106] also provided quasiglobal
schemes for methane, propane, benzene, and iso-octane with an initial
transformation of the hydrocarbon into CO and H 2 by one or two 1 global
stages, similar to Equation (A.4). In the mechanism developed by Hautman
et al. [172], intermediates are generally represented by ethene (C 2 H 4 ), regardless
of the actual main reactants. Unlike the quasi-global reaction schemes
discussed so far, the one by Jones and Lindstedt [199] involves two competing
fuel breakdown reactions. Oxygen as well as water are considered to be
involved in the global fuel oxidation step. However, this set of reactions was
1 Duterque et al. [106] consider individual intermediate species for different hydrocarbons.
201