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

B.2 Supplementary Data on Numerical Simulations
it is shown in relation to an ignition position that is coupled with the local
equivalence ratio φ r (see Fig. 5.4). In the case of a spatially fixed ignition
position of r m,in = 0.8×10 −3 m, the respective value is ˙q v = 7.43×10 9 W m −3
(cf. Fig. 4.3), which is also the asymptotic value in Figure B.1 for r → ∞.
In Figure 5.5, the initial mass of the fuel droplet m fuel,0 is used as the basis
for the calculation of the emission index EI NOx . Different values are obtained
when relating the NO x emissions to the reacting fuel mass m fuel,reac instead.
Figure B.2 illustrates the relative deviation between these two relations by
∆EI NOx . The overall trends are similar. At low degrees of vaporization Ψ, the
emission indices are nearly identical and ∆EI NOx is close to zero. With an increase
of Ψ, the difference increases between the two calculation approaches.
It reaches its maximum at Ψ= 0.8 with the relative deviation of ∆EI NOx = 42%
or an absolute value of EI NOx = 0.98 g NOx /kg fuel [297].
40
%
Pre-vaporization rate Ψ
Relative deviation ∆EINOx
30
20
10
0
Ignition fixed,
heat sink fixed
Ignition variable,
heat sink at fixed position
Ignition variable,
heat sink at fixed distance
0.0 0.2 0.4 0.6 0.8 1.0
Figure B.2: Relative Deviation of Emission Index by Relating NO x Emissions to Different
Fuel Masses. Relating the emission index EI NOx to the reacting fuel mass m fuel,reac
instead of the initial droplet mass m fuel,0 results in a relative deviation of ∆EI NOx
(cf. Fig. 5.5) [297].
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