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Download: Mechanism,
Thermochemical, and Transport Databases in
ChemKin format.
Release notes: This interim version
of JetSurF consists of 194 species and 1459 reactions. The model describes the pyrolysis and
oxidation kinetics of normal alkanes up to n-dodecane at high temperatures.
The model is
“un-tuned” and work-in-progress. The development effort centers on achieving
consistent kinetic parameter assignment and predictions for a wide range of
hydrocarbon compounds. This effort is
reflected in the validation tests documented in the Performance
that we know page.
The base model is USC-Mech II
(111 species, 784 reactions) that describes the oxidation of H2 and CO
and the high-temperature chemistry of C1-C4 hydrocarbons.
The base model considers the pressure dependence for unimolecular and bimolecular chemically activated
reactions, and was validated against experimental data ranging from laminar
flame speeds, ignition delay times behind shock waves, to species profiles in
flow reactors and burner stabilized flames. The base model is appended with a set of reactions (83
species and 675 reactions) to describe high-temperature pyrolysis and
oxidation of normal alkanes (CkH2k+2, 5 ≤
k ≤ 12). The following class of major reactions of n-alkanes have been considered: |
|
Reaction type |
Source and Method
of Rate Estimation |
Pressure |
|
C-C bond fission in n-alkane |
Back rate constant from 2C2H5
→ n-C4H10
(k∞) |
No |
|
H-abstraction by H, O, OH, O2, and CH3 |
Cohen’s method. Used the rate constants of C3H8
+ X → n-C3H7 or i-C3H7 + HX |
N/A |
|
Mutual isomerization of alkyl radicals (1,4,
1,5 and 1,6 H-shift) |
Tsang,
Manion and co-workers. n-pentyl
[1], n-hexyl [2], n-heptyl [3], n-octyl [4]. Rate parameters for the CkH2k+1
(9≤ k ≤ 12) radicals
are equal to those of n-octyl [4]. |
Yes |
|
All possible C-C bond beta-scission in alkyl radicals |
See
above |
Yes |
|
C-C bond fission
reactions kinetic parameters for C5-C12 alkenes as well
as mutual isomerization and C-C bond b-scission of alkenyl radicals are based on the
work of Tsang and coworkers [5, 6] on 1-hexenyl and 1-pentenyl radicals. H-abstractions kinetic
parameters are based on those of similar reactions of C3 and C4
species in USC-Mech II. Thermochemical properties for C>4
alkane, alkyl and alkene species were estimated from the group additivity
method using group values consistent with those in USC-Mech II. Additionally, a 4-species, 12-step n-dodecane oxidation model is appended
to capture some of the low- to intermediate-temperature chemistry. The lumped model is an adaptation
of that proposed by Bikas and Peters [6]. The use of this model does not
offer the possibility to closely predict the low-temperature chemistry, but
it enables a better understanding of the impact of low- to
intermediate-temperature chemistry on n-dodecane
oxidation at high temperatures. |
|
1.
W. Tsang, J. A. Walker, J. A. Manion, Proceedings of the Combustion Institute 27 (1998) pp.135-142. 2. W. Tsang, J. A. Walker, J. A. Manion, Proceedings of the Combustion Institute
31 (2007) pp.141-148. 3. W. Tsang, I. A. Awan, W. S. McGivern, J. A.
Manion, Soot precursor from real fuels: the unimolecular reaction of fuel radicals. In Combustion Generated Fine Carbonaceous
Particles (H. Bockhorn, A. D’Anna, A. F. Sarofim, H. Wang, Eds.), Karlsruhe University
Press, in press, 2008. 4. W. Tsang,
W. S. McGivern, J. A. Manion, Proceedings of the Combustion Institute,
in press (2008). 5. W. Tsang, J. Phys. Chem. A
110 (2006) 8501-8509. 6. W. Tsang,
“ PrIMe: A Database for the Pyrolysis of Heptane and Smaller Hydrocarbons
Fuels; Implications for Realistic Fuels.” Poster Paper,
32nd International Symposium on Combustion, 2008. 7. G. Bikas, N. Peters, Combustion and Flame 126 (2001) 1456-1475. |