If the system of interest has been modeled by previous workers in the field, it may be possible to find a complete set of files that constitute a chemistry set, or published literature that provides a reaction mechanism. This is fairly common for combustion systems, but much less so for materials processing or industrial chemical systems.

One example of an established reaction mechanism is for methane combustion and was developed under funding from the Gas Research Institute. " GRI-mech" is currently at version 3.0. This reaction mechanism, which consists of set of gas-phase chemistry, thermodynamic and transport data files, is provided as one of the default chemistry sets in Ansys Chemkin. A detailed description of the development and extensive validation of this mechanism is available [9].

Lawrence Livermore National Laboratory has posted combustion mechanisms [10]. This site includes thermodynamic data, transport data, and reaction sets for flame simulations with hydrogen and hydrocarbon fuels from methane up to iso-octane.

Other web sites on the Data Links page that provide combustion mechanisms include the E.N.S.I.C. Department de Chimie Physique des Reactions in Nancy, France, the University of Chalmers, the University of Leeds in the UK, Eötvös University (ELTE) in Hungary, the University of Southern California, and the University of California-San Diego.

A much larger number of reaction mechanisms have been published in the literature than have been posted on the web. A good search of the literature should yield reaction mechanisms for many reacting flow systems. A request to the authors will often result in electronic files containing the mechanism, either as an Ansys Chemkin file or a closely related format. This can eliminate the error-prone task of typing in all the reactions and rates from a hard-copy publication.

Finally, Ansys staff have worked on mechanism or chemistry-set development for a number of materials-processing systems. Chemistry-set files for such mechanisms that have been published are available upon request. For other cases, customers can access Ansys’s contract consulting services to aid in chemistry development.

The sample problems and tutorials included with the Ansys Chemkin software include chemistry sets for relatively simple systems. These chemical data are provided for the purpose of illustration and training, and should be used with caution for any other program. Although they are generally derived from solid technical work, they may represent early work that is now obsolete, or they may be small parts of more complete reaction mechanisms or mechanisms with extremely limited applicability.