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

Chapter 4
0.3
φ=0.8
Su (m/s)
0.2
0.1
0.0
1 2 3 4 5 6
Pressure (bar)
0.4
0.3
φ=1.0
tel-00623090, version 1 - 13 Sep 2011
Su (m/s)
0.2
0.1
0.0
1 2 3 4 5 6
Pressure (bar)
Figure 4.31 - Burning velocity versus pressure for fluidized bed syngas-air mixture at various
equivalence ratios.
The lower limit for the inquiry region have been defined by Fiock and Marvin, (1937)
and Rakotoniana, (1998), respectively, for the regime after the first 25% and 50% of
flame propagation, when the pressure could be measured with sufficient accuracy. In
this work the criterion was the stretch rate, due to its influence on burning velocity.
The flame speeds, S n , are obtained by plotting values of r b obtained from Eq. (4.13) as
a function of time and determining the slopes of dr b /dt. With the relationship between
the values of r b and S n , the value of flame stretch, κ, can be specified from Eq. (4.2) for
expanding spherical flames. Figures 4.32-4.34 shows stretch rate versus pressure for
typical syngas-air mixtures under study at various equivalence ratios.
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