Version 2.11 expands GRI-Mech 1.2 by including nitrogen chemistry relevant to natural gas chemistry and reburning. It contains 277 elementary chemical reactions of 49 species.
GRI-Mech 2.11 replaces GRI-Mech 2.1, correcting two minor errors.

Version 2.11 contains the chemistry identical to that of version 1.2 but adds 102 reactions of 17 additional nitrogen-containing species. The parameters of the 175 reactions from version 1.2 were not varied in the course of the Version 2.11 optimization process except for the rate coefficient of the CH + H2O --> H + CH2O reaction, which was found to play an important role in prompt NO formation but to have no effect on the course of the carbon-hydrogen- oxygen chemistry of methane combustion. Version 2.11 is therefore identical to version 1.2 with respect to the carbon-hydrogen-oxygen chemistry of natural gas ignition and flames.

Version 2.11 was not optimized for modeling pure nitrogen- hydrogen-oxygen chemistry or any form of NOx removal process except for reburning.

In the course of developing GRI-Mech 2.11 we learned quite early that optimizing the nitrogen chemistry relevant to natural gas flames and reburning is qualitatively a very different challenge than optimizing the carbon-hydrogen-oxygen chemistry. In the first place, we were able to locate only a much smaller data base of experimental information from which to draw optimization targets. Then, once the modeling process had proceeded far enough that we could examine matches between computed and observed behavior, we found a far higher degree of discord among the matches to targets and other data than we had seen in working with our earlier optimizations of carbon-hydrogen-oxygen chemistry. We therefore have to caution users of GRI-Mech 2.11 to regard it only a preliminary starting point that can not be applied with anything like the degree of confidence that can be attached to the version 1.2 carbon-hydrogen-oxygen chemistry. We do believe that GRI-Mech 2.11 is an improvement for the experiments modeled over previous attempts to describe NOx formation and removal in natural gas flames, for example the 1989 Miller and Bowman mechanism, and are therefore releasing it at this time in the spirit of 'beta testing' our first optimized result and stimulating further experimental study of NOx formation and removal in natural gas flames.


The following files can be loaded into your computer (you may need to select a load to disk option in your Web browser)

grimech211.dat A reaction mechanism and rate coefficient file, in Chemkin format
thermo211.dat A thermochemical data file to be used with grimech211.dat, as NASA polynomial coefficients
readme211.dat Same as the present home page
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 selected user questions, comments, and suggestions related to the implementation of GRI-Mech

These files may also be obtained by anonymous ftp from unix.sri.com, the directory gri.


To cite GRI-Mech 2.11, please refer to this Web page: C.T. Bowman, R.K. Hanson, D.F. Davidson, W.C. Gardiner, Jr., V. Lissianski, G.P. Smith, D.M. Golden, M. Frenklach and M. Goldenberg, http://www.me.berkeley.edu/gri_mech/


The rate parameters of the additional 102 reactions of nitrogen-containing species were optimized against the following experimental targets (measurement uncertainties, when reported by the cited investigators, are indicated):

NF1 Maximum NO concentration SRI Flame: Heard, D.E., et al., Combust. Flame 88:137 (1992)

phi = 1.13, P = 30 torr

NF2 Location of CH maximum
NF3 CH half-width
NFR1 HCN relative concentration Flow Reactor: Glarborg, P., and Miller, J.A., Combust. Flame 99:475 (1994)

318 ppm-1710ppm-2.4%-2.8%-94.56%
P = 798 torr

NFR2 NO relative concentration
NFR3 N2O relative concentration
NF6 Maximum NO mole fraction Sandia Flame: Miller, J.A., et al., 20th Symp. Int. Combust., 1984, p. 673

phi = 1.5, P = 25 torr

NF7 Maximum CN mole fraction
NF8 Maximum CH mole fraction UTRC Flame: Zabielski, M.F. and Seery, D.J., GRI Report 84/0126, 1984


NF9 Maximum CN mole fraction
NF10 NO removed
NF11 Ratio of CH peak concentrations at two levels of NO doping NRL Flame: Williams, B.A., and Fleming, J.W., Combust. Flame 98:93 (1994)

CH4-O2-Ar-NO or N2O
phi = 1.0, P = 10 torr

NF12/13 Ratio of CN peak concentrations for NO and N2O doping

Selecting an individual item from this list will describe this target, display a sensitivity diargam, and present the numerical prediction of GRI-Mech 2.11 for this target.


Version 2.11 contains the chemistry identical to that of version 1.2 and therefore the performance of GRI-Mech 2.11 is identical to GRI-Mech 1.2 with respect to the carbon-hydrogen-oxygen chemistry of natural gas ignition and flames.

Here is a list of the validation checks of Version 2.11 that we have made (measurement uncertainties, when reported by the cited investigators, are indicated):

Flow Reactors

Low-Pressure Flames

Stirred Reactors

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