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

4 Numerical Modeling and Simulation
1.50
1.40
Experiments (Xu et al., 2003)
Simulation
mm s −1 Initial droplet diameter D 0
Burning rate k
1.30
1.20
1.10
1.00
0.8 1.0 1.2 1.4 1.6 mm
Experi-
Figure 4.10: Evaluation of Burning Rate for Different Initial Droplet Diameters.
ments and numerical simulations were conducted at T ∞ = 1093K [465].
to the fact that the effects of radiation and soot formation, as for instance reported
in Nakaya et al. [307, 309] and Xu et al. [465, 467], are not taken into
account in the present single droplet model. Besides, this particular validation
test case at T ∞ = 1093 K yields the same k-value for droplets burning due
to auto-ignition as well as due to forced ignition by an external heat source
(cf. Chap. 4.3). However, auto-ignition requires more ignition delay time than
forced ignition.
4.7 Scope and Limitations of Single Droplet Combustion
Utilizing the one-dimensional single droplet model, as outlined above (see
Chap. 4.5), it is not possible to investigate two or more droplets including
their interactions. Effects of convective flow cannot be studied either. On the
other hand, detailed chemistry modeling, as required within this study, necessitates
massive computational resources. The computation of a full geometry
comparable to the one of Chapter 3.3 with detailed chemistry is infeasible at
present and will remain to be so for the foreseeable future. However, it may
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