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

2 Combustion Theory
2.3 Kinetic Modeling
This chapter reviews the fundamentals of kinetic modeling of hydrocarbon
combustion. It is intentionally included in the combustion theory of
Chapter 2, as the chemical mechanisms employed are well-established in
combustion technology. However, this chapter also provides a link to the
following chapters with a very particular approach on kinetic modeling. It
aims at providing a reliable, compact hydrocarbon mechanism including NO x
chemistry. The proposed approach was also applied in the numerical modeling
of the present thesis (Chap. 4). Moreover, a significant number of studies
were previously carried out aiming for simplified chemical kinetic models
[89, 94, 167]. For instance, Dagaut [93] investigated different model fuels
for kerosene oxidation. Surrogate fuels for diesel engines were examined by
Bounaceur et al. [49] and Pitz et al. [340]. In all three publications, n-decane
(C 10 H 22 ) yielded the best modeling of kerosene and diesel combustion. 14
To capture the formation of soot, which is influenced by aromatics, it would
be necessary to use more complex model fuels containing polyaromatic compounds.
However, multi-component fuels and soot formation are not considered
here due to the focus on NO x formation and a general trade-off between
model complexity and computational cost. Hence, pure C 10 H 22 is the fuel of
choice for the scope of this work [297, 298].
2.3.1 Hydrocarbon Mechanism
As pointed out by Moesl et al. [297, 298], there are only two reaction mechanisms
for n-decane that are applicable here, meaning they are sufficiently
precise but with a species number not significantly above 100. The mechanisms
of Honnet et al. [182] and Zhao et al. [474] include auto-ignition, are
valid for wide ranges of temperature and pressure, and are limited to a reasonable
number of species. The C 10 H 22 mechanism developed by Honnet et al.
[182] is based on the work of Bikas and Peters [43, 44]. The mechanism compiled
by Zhao et al. [474] is an improvement of the work of Zeppieri et al. [473].
14 n-Heptane (C 7 H 16 ) is a minor component in practical fuels but often used as a model fuel in technical applications,
as well [31, 175, 304, 340].
40