Etude de la combustion de gaz de synthèse issus d'un processus de ...

Experimental set ups and diagnostics
high pressure auto-ignition of combustible mixtures as it gives direct measure of
ignition delay (Mittal, 2006). When the interest is the heat transfer to the walls then it is
usually used an inert gas, with equal adiabatic coefficient as the reacting mixture, as a
test gas. In this work instead of an inert gas a stoichiometric syngas-air mixture was
used out of auto-ignition conditions. A set of three experiments were made for each
syngas composition without combustion in order to verify its repetition. The pressure
traces are shown in figure 3.9 for downdraft syngas composition.
Figure 3.9 shows rapid rise in pressure during the compression stroke followed by
gradual decrease in pressure due to heat loss from a constant volume chamber, the
clearance volume, at the end of compression. A very good repetition of signals was
found during compression experiments being the maximum difference between
pressure peaks around 0.3 bar (25 bar on average) from one experiment to another.
tel-00623090, version 1 - 13 Sep 2011
Pressure (bar)
30
25
20
15
10
5
0
Shot 1
Shot 2
Shot 3
90 100 110 120 130 140 150 160 170 180
Time (ms)
Figure 3.9 - Pressure versus time for compression of stoichiometric downdraft syngas-air in a
RCM. Initial conditions: P i = 1.0 bar; T i = 293 K, ε=11.
1200
1000
Volume (cm 3 )
800
600
400
200
0
0 5 10 15 20 25 30 35 40 45 50
Time (ms)
Figure 3.10 - Typical volume trace for compression of stoichiometric downdraft syngas -air in an
RCM. Initial conditions: P i = 1.0 bar; T i = 293 K, ε=11.
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