Optimization and Computational Fluid Dynamics - Department of ...

2 A Few Illustrative Examples of CFD-based Optimization 45
Air mass flow-rate in primary inlet [g/s]
1.5
1
0.5
0
0.04 0.06 0.08
Methane mass flow-rate in primary inlet [g/s]
200
180
160
140
120
100
80
60
40
20
0
Fig. 2.15 Contour plot of the temperature variation (in K) as function of the input
parameters
Table 2.5 Primary inlet flow-rates for the selected simulations
Figure number Primary injector: Primary injector:
Methane mass flow rate [g/s] Air mass flow rate [g/s]
Fig. 2.18 7.19 × 10 −2 7.49 × 10 −1
Fig. 2.19 4.92 × 10 −2 8.31 × 10 −1
mixtures, injected through the primary and the secondary inlet and leading
to the shortest possible flame.
The mass fraction field of CO obtained for the two-dimensional burner
considered here at two chosen compositions of the two inlets are presented
in Figs. 2.18 and 2.19. In both figures, the mass fraction of the radical HCO
is also shown on the right side to visualize the shape and position of the
active reaction zone. Figure 2.18 corresponds to a non-optimal solution of
the EA. Compared with the optimal solution in Fig. 2.19, a large CO mass
fraction and thus CO mass-flow rate is found at the outlet of the combustion
chamber for this set of compositions. These two figures employ the same
gray-scale values to facilitate comparisons.
The values chosen by the optimization procedure for the primary inlet for
the cases corresponding to Figs. 2.18-2.19 are listed in Table 2.5. Consid-
0.1