Troels Dyhr Pedersen.indd - Solid Mechanics

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Arrows in the scheme indicate the dominating reaction way. Percentage numbers indicate
the approximate distribution on the paths.
The radicals that are placed in the small boxes e.g. [+ OH] denotes that this radical reacts
with the radical in the larger box in which it resides. If no radical is in the box, the
reaction is by decomposition. An M denotes a third body collision.
References to reaction numbers are to the numbers used in the original mechanism. The
reason is that this makes it easier to identify the reactions in the original scheme.
10.4 Comparison of the full and the reduced schemes
To evaluate the performance of the reduced scheme against the complete scheme, the two
schemes were tested in a CHEMKIN simulation with identical parameters. The heat
release and accumulated heat release are plotted in figures 9 and 10.
Heat release [J/CAD]
700
600
500
400
300
200
100
Comparision of full and reduced mechanism heat release
Full mechanism
Reduced mechanism
0
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CAD
0 5
Figure 9: Simulated heat release for the full and reduced mechanisms
Accumulated heat release
[J]
1200
1000
800
600
400
200
Comparision of full and reduced mechanism accumulated heat release
Full mechanism
Reduced mechanism
0
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CAD
0 5
Figure 10: The accumulated heat release of the full and reduced mechanisms
It is noted that the ignition timing is perfectly preserved with the reduced scheme. All
initial reactions with DME were included in the reduced scheme to preserve the
mechanism behavior in the first stages of combustion.