tut1.m

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tut3.m

Warning

This documentation is for an old version of Cantera. You can find docs for newer versions here.

# tut2.m¶

% Tutorial 2: Working with input files
%
%   Topics:
%     - using functions 'importPhase' and 'importInterface'
%     - input files distributed with Cantera
%     - the Cantera search path
%     - CTML files
%     - converting from CK format
%
help tut2

t0 = cputime;

% In the last tutorial, we used function GRI30 to create an object
% that models an ideal gas mixture with the species and reactions of
% GRI-Mech 3.0. Another way to do this is shown here, with statements
% added to measure how long this takes:

gas1 = importPhase('gri30.cti', 'gri30');
msg = sprintf('time to create gas1: %f', cputime - t0)

% Function 'importPhase' constructs an object representing a phase of
% matter by reading in attributes of the phase from a file, which in
% this case is 'gri30.cti'. This file contains several phase
% spcifications; the one we want here is 'gri30', which is specified
% by the second argument.  This file contains a complete specification
% of the GRI-Mech 3.0 reaction mechanism, including element data
% (name, atomic weight), species data (name, elemental composition,
% coefficients to compute thermodynamic and transport properties), and
% reaction data (stoichiometry, rate coefficient parameters). The file
% is written in a format understood by Cantera, which is described in
% the document "Defining Phases and Interfaces."

% On some systems, processing long CTI files like gri30.cti can be a
% little slow. For example, using a typical laptop computer running
% Windows 2000, the statement above takes more than 4 s, while on a
% Mac Powerbook G4 of similar CPU speed it takes only 0.3 s. In any
% case, running it again takes much less time, because Cantera
% 'remembers' files it has already processed and doesn't need to read
% them in again:

t0 = cputime;
gas1b = importPhase('gri30.cti', 'gri30');
msg = sprintf('time to create gas1b: %f', cputime - t0)

% CTI files distributed with Cantera
%-----------------------------------

% Several reaction mechanism files in this format are included in the
% Cantera distribution, including ones that model high-temperature
% air, a hydrogen/oxygen reaction mechanism, and a few surface
% reaction mechanisms. Under Windows, these files may be located in
% 'C:\Program Files\Common Files\Cantera', or in 'C:\cantera\data',
% depending on how you installed Cantera and the options you
% specified.  On a unix/linux/Mac OSX machine, they are usually kept
% in the 'data' subdirectory within the Cantera installation
% directory.

% If for some reason Cantera has difficulty finding where these files
% are on your system, set environment variable CANTERA_DATA to the
% directory where they are located. Alternatively, you can call function

% Cantera input files are plain text files, and can be created with
% any text editor. See the document 'Defining Phases and Interfaces'

% Importing multiple phases or interfaces
% ---------------------------------------

% A Cantera input file may contain more than one phase specification,
% or may contain specifications of interfaces (surfaces). Here we
% import definitions of two bulk phases and the interface between them
% from file diamond.cti:

gas2 = importPhase('diamond.cti', 'gas');        % a gas

diamond = importPhase('diamond.cti','diamond');  % bulk diamond

diamonnd_surf = importInterface('diamond.cti','diamond_100',...
gas2, diamond);

% Note that the bulk (i.e., 3D) phases that participate in the surface
% reactions must also be passed as arguments to importInterface.

% CTML files
% ----------

% Note that when Cantera reads a .cti input file, wherever it is
% located, it always writes a file of the same name but with extension
% .xml *in the local directory*. If you happen to have some other file
% by that name, it will be overwritten. Once the XML file is created,
% you can use it instead of the .cti file, which will result in
% somewhat faster startup.

gas4 = importPhase('gri30.xml','gri30');

% Interfaces can be imported from XML files too.
diamonnd_surf2 = importInterface('diamond.xml','diamond_100',...
gas2, diamond);

% Converting CK-format files
% --------------------------

% Many existing reaction mechanism files are in "CK format," by which
% we mean the input file format developed for use with the Chemkin-II
% software package. [See R. J. Kee, F. M. Rupley, and J. A. Miller,
% Sandia National Laboratories Report SAND89-8009 (1989).]

% Cantera comes with a converter utility program 'ck2cti' (or
% 'ck2cti.exe') that converts CK format into Cantera format. This
% program should be run from the command line first to convert any CK
% files you plan to use into Cantera format. This utility program can