case-khalifa/constant/gri-belhi/readme30.dat

The information in this document can also be accessed on the World Wide Web 
at     http://www.me.berkeley.edu/gri_mech/

  or through the Gas Research Institute GRINet home page at
                   http://www.gri.org
point to the 'Basic Research' button, and then to 'GRI-Mech'

At this Web location you can also view results of validation tests, directly 
load the GRI_Mech files, and check on any late-breaking news available.

Files in this directory:

README30.DAT   This file.

GRIMECH30.DAT  A reaction mechanism and rate coefficient file, in Chemkin
                format, describing 276 reactions of 49 species. It includes
                reactions of nitrogen-containing species relevant to the NOx
                chemistry of natural gas combustion and reburning.
                A corrected version of the mechanism was posted 11/4/95.

THERMO30.DAT   A thermochemical data file to be used with GRIMECH21.DAT,
                as sets of "NASA polynomial" coefficients.

TRANSPORT.DAT   A file containing the parameters needed for calculating 
                transport coefficients to be used in the Sandia flame code.

BUGFIX.DAT      A file containing information on bugs found in using GRI-Mech
                in various computer codes.


The files in this directory are products of computational and experimental
research sponsored by the Gas Research Institute. 
The research was carried out at Stanford University, The University of
California, Berkeley, The University of Texas at Austin, and SRI International.

GRI-Mech is an optimized (see below) detailed chemical reaction mechanism
capable of the best representation of natural gas flames, ignition, and NOx
formation and reburning in natural gas combustion that we are able to
provide as of the date at the head of this file.

In order to use the input files directly you need the Sandia National
Laboratory "Chemkin-II" programs. (See discussion below.) Ignition and flow
reactor profiles and well-stirred reactor outputs calculated with this mechanism
and thermochemical data should be independent of the program used to compute
them; noticeable small differences in flame profiles should be expected if you
use a flame code other than Premix, however, because the transport calculation,
the numerical method of solving the partial differential equations, and so on,
differ from program to program.

Before telling you more we are obliged to say:

       *******************    GRI  DISCLAIMER   ********************

       LEGAL NOTICE   These files, both the ones intended for use

       as computer input as well as those comprising documentation,

       were prepared by Stanford University, SRI International,

       The University of California, Berkeley, and The University of

       Texas at Austin as a result of research sponsored by the

       Gas Research Institute (GRI).


       Neither GRI, members of GRI, nor any person acting on behalf of

       either:



       a. Makes any warranty or representation, express or implied,

       with respect to the accuracy, completeness, or usefulness

       of the information contained in these files, or that the use

       of any data, method, or process disclosed in these files

       may not infringe privately owned rights; or



       b. Assumes any liability with respect to the use of, or for

       damages resulting from the use of, any information,

       data, method or process disclosed in these files.

       ************************************************************ 

Now that you have read our disclaimer, here is what you can find in
this README file:

1. A description of the version 3.0 GRI-Mech release files.

2. A short summary of what we can tell you about its performance.
   Much more detail is available on the Web page.

3. A request for feedback on your experience with it.

4. How to get in touch with us.

5. Some cautionary notes.



1. WHAT IS GRI-Mech 3.0?

What follows is a brief overview of the GRI-Mech 3.0 mechanism.

GRI-Mech 3.0 is a compilation of 325 elementary chemical reactions and
associated rate coefficient expressions and thermochemical parameters for
the 53 species involved in them.

It differs from the version 2.11 mechanism that it succeeds in that we
have updated the kinetics and targets, and have also expanded the chemistry.
New formaldehyde intermediate oxidation targets, prompt NO
targets and reburn targets are added.  The kinetics now includes a
better description of the oxidation products of C2 intermediates, and
a shortened submechanism for propane oxidation as a minor natural gas
constituent representing the higher molecular weight components was
added.
If you have the Chemkin programs, all you need to do is substitute the 
GRI-Mech 3.0 input files for whatever files you have working with Chemkin
before(including versions 1.2 or 2.11) and you will be ready to go.

2. VERSION 3.0 PERFORMANCE THAT WE KNOW ABOUT

We test the performance of GRI-Mech extensively. Details are shown on
the Web page http://www.me.berkeley.edu/gri_mech/.  The lengthy list is
not repeated here.
The performance of version 3.0 is generally improved over version 2.11.
The major results of the new mechanism optimization are:
1. Deviations from target values are generally less than previously.
2. Similar values for the key rates CH3+H, CH3+OH, & CH3+O2 were found.
3. Adding CH2O targets required no changes to our new values for CH2O+M or H.
4. Only HCN thermodynamics is sensitive.  JANAF value was changed.
5. An improved prompt NO target increases the CH + N2 rate constant.
6. New lower experimental flame speeds remain overpredicted.

A very limited subset of propane chemistry was added to version 3.0,
14 reactions and 2 species.  The sole purpose of this addition and the
few propane shock tube ignition delay targets is to represent the
minority higher molecular weight components of natural gas.  It is not
intended to model propane combustion.

The sparseness of nitrogen targets for NO formation and reburn, noted
in version 2.11, remains a problem - although several new targets have
been incorporated into version 3.0. An addendum optimization is being
prepared to add deNOx kinetics to the mechanism (version 3.1).

3. PLEASE  TELL  US  WHAT  YOU  LEARN,  AND  ABOUT  YOUR PROBLEMS

While the authors are continuing to expand their understanding of how
GRI-Mech works, it is only natural that others will see things that should be
done with quite different perspectives.  We would very much like to hear
from you.

We want to hear about your experiences with GRI-Mech, both successes and
failures.  It will help us more in our development work, and consequently all
users of our later releases, to hear about failures.  We welcome suggestions of
any kind. Please be as specific as you can in telling us about your results
and your problems.  We will be happy to include the results of your "validation
runs", with appropriate citation to you, in our printed materials.

We are especially interested in maintaining a list of users, so that we can
quickly communicate changes, problems, and updates.

Since our ftp daemon does not record actual usernames, we request that those
who are considering use of the mechanism send us their e-mail addresses.
Please address them to SMITH@MPLVAX.SRI.COM.



4. HOW TO CONTACT THE AUTHORS

We can be reached at any of the addresses given below.

Bob Serauskas at GRI is the Program Manager of this project. If you have an
official question, he is the person to contact. Bob's phone number is
312-399-8208, his mailing address is c/o Gas Research Institute, 8600 West Bryn
Mawr Avenue, Chicago, Illinois 60631-3562, his Internet address is
rserausk@gri.org, and his fax number is 312-399-8170.

For scientific questions please contact Greg Smith or one of the other authors
listed below:

University of California, Berkeley:

Michael Frenklach   (myf@euler.berkeley.edu)

Nigel Moriarty   (mgold@euler.berkeley.edu)

Stanford University:

Tom Bowman   (bowman@navier.stanford.edu)

SRI International:

Greg Smith   (smith@mplvax.sri.com)

University of Texas at Austin:

Bill Gardiner     (bill@lioness.cm.utexas.edu)

To cite GRI-Mech, please refer to our World Wide Web location 



5. SOME CAUTIONARY NOTES

First we want to warn you about several general aspects of GRI-Mech.

a. PLEASE DO NOT MAKE ANY SUBSTITUTIONS!

Or if you MUST so, be very careful. GRI-Mech has been optimized as a whole,
and should be used just as you receive it if you want to duplicate its ability
to model natural gas combustion and NO formation and removal.

You likely will not surpass the performance we obtained for natural gas
combustion and NO formation and removal by the independent adjustment of any
"sensitive" reaction rate parameters.

Any substitution of "better" rate coefficient expressions or removal of
species or reactions may lead to your getting significantly deteriorated
performance of the mechanism when tested against the whole spectrum of natural
gas combustion and NO data.

We recognize that GRI-Mech users are human and will adjust rate coefficients or
make major changes for specific purposes, such as doing sensitivity analyses.
When doing this please keep in mind that we do not claim that GRI-Mech is
suitable as a starting point for mechanism development by patchwork means.
We cannot predict what the consequences may be.

b. NUMBERS OF SPECIES AND REACTIONS.

The list of reactions and species in GRI-Mech 3.0 contains entries that are
"unimportant" for natural gas combustion and NO formation and removal
for the conditions investigated to date.

There are several reasons why we have them there. One is that there are special
purposes (like models of flame radiation or pollutant emissions) where
elementary reactions that are otherwise negligible become important, and we
want to have these reactions on hand for such occasions. A second reason is
that the combustion of some other fuels (methanol, acetylene, ...) can be
modeled using GRI-Mech as a subset, with the knowledge that the part of the
mechanism relevant to natural gas has been optimized in the manner described
in the documentation for GRI-Mech 3.0. [We have not looked into the performance
of the GRI-Mech for any fuels except methane, ethane, hydrogen and carbon
monoxide.]

There are techniques for reducing reaction and species lists that you may want
to use yourself on GRI-Mech 3.0; please see the relevant comments in the
documentation.  Reduction methods have been applied to version 1.2.

c. Back reactions.  We consider all reactions to be reversible, even though
it is clear on thermochemical grounds that negligible reverse flux will
occur in many reactions. If your modeling program requires explicit
inclusion of reverse reactions, GRI-Mech 3.0, as presented in this directory,
will require additional calculations to find out which of them are really 
needed.

d. Computer time. The numerous species and reactions in GRI-Mech, some of which
really do not need to be included for modeling natural gas combustion and NO
formation and removal, increase the demand on computer resources for doing the
chemical part of the model by a large factor.  We accept this in order to avoid
coping with the numerous problems that arise in streamlining such
computations.  Computer time has not been a problem for us even when using
GRI-Mech on small workstations and fast PCs.