research/cantera
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

[Doc] Add description of chemically activated reactions to CTI guide

Browse source
This commit is contained in:
Ray Speth 2013-07-06 21:44:13 +00:00
parent 08724c9ac3
commit 1cc411200e
2 changed files with 41 additions and 0 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

3
doc/sphinx/cti/classes.rst
View file

@ -106,6 +106,9 @@ Reactions
.. autoclass:: ctml_writer.falloff_reaction
:no-undoc-members:
.. autoclass:: ctml_writer.chemically_activated_reaction
:no-undoc-members:
.. autoclass:: ctml_writer.pdep_arrhenius
:no-undoc-members:

38
doc/sphinx/cti/reactions.rst
View file

@ -291,6 +291,44 @@ the "SRI" falloff function. It is implemented by the :class:`SRI` directive.
function, which has a C++ implementation, but doesn't appear to be implemented
in the CTI or CTML parsers.
Chemically-Activated Reactions
==============================
For these reactions, the rate falls off as the pressure increases, due to
collisional stabilization of a reaction intermediate. Example:
.. math::
\mathrm{Si + SiH_4 (+M) \leftrightarrow Si_2H_2 + H_2 (+M)}
which competes with:
.. math::
\mathrm{Si + SiH_4 (+M) \leftrightarrow Si_2H_4 (+M)}
Like falloff reactions, chemically-activated reactions are described by
blending between a "low pressure" and a "high pressure" rate expression. The
difference is that the forward rate constant is written as being proportional
to the *low pressure* rate constant:
.. math::
k_f(T, P_r) = k_0 \left(\frac{1}{1 + P_r}\right) F(T, P_r)
and the optional blending function *F* may described by any of the
parameterizations allowed for falloff reactions. Chemically-activated
reactions can be defined using the :class:`chemically_activated_reaction`
directive.
An example of a reaction specified with this parameterization::
chemically_activated_reaction('CH3 + OH (+ M) <=> CH2O + H2 (+ M)',
kLow=[2.823201e+02, 1.46878, (-3270.56495, 'cal/mol')],
kHigh=[5.880000e-14, 6.721, (-3022.227, 'cal/mol')],
falloff=Troe(A=1.671, T3=434.782, T1=2934.21, T2=3919.0))
In this example, the units of :math:`k_0` (`kLow`) are m^3/kmol/s and the
units of :math:`k_\infty` (`kHigh`) are 1/s.
Pressure-Dependent Arrhenius Rate Expressions (P-Log)
=====================================================