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

tut5.m¶

% Tutorial 5:   Reaction information and rates
%
%    Topics:
%       - stoichiometric coefficients
%       - reaction rates of progress
%       - species production rates
%       - reaction equations
%       - equilibrium constants
%       - rate multipliers
%
help tut5

g = GRI30;
set(g,'T',1500,'P',oneatm,'X',ones(nSpecies(g),1));

% Methods are provided that compute many quantities of interest for
% kinetics. Some of these are:

% 1) Stoichiometric coefficients

nu_r   = stoich_r(g)    % reactant stoichiometric coefficient mstix
nu_p   = stoich_p(g)    % product stoichiometric coefficient mstix
nu_net = stoich_net(g)  % net (product - reactant) stoichiometric
% coefficient mstix

% For any of these, the (k,i) matrix element is the stoichiometric
% coefficient of species k in reaction i. Since these coefficient
% matrices are very sparse, they are implemented as MATLAB sparse
% matrices.

% 2) Reaction rates of progress

% Methods rop_f, rop_r, and rop_net return column vectors containing
% the forward, reverse, and net (forward - reverse) rates of
% progress, respectively, for all reactions.

qf = rop_f(g);
qr = rop_r(g);
qn = rop_net(g);
rop = [qf, qr, qn]

% This plots the rates of progress
figure(1);
bar(rop);
legend('forward','reverse','net');

% 3) Species production rates

% Methods creationRates, destructionRates, and netProdRates return
% column vectors containing the creation, destruction, and net
% production (creation - destruction) rates, respectively, for all species.

cdot = creationRates(g);
ddot = destructionRates(g);
wdot = netProdRates(g);
rates = [cdot, ddot, wdot]

% This plots the production rates
figure(2);
bar(rates);
legend('creation','destruction','net');

% For comparison, the production rates may also be computed
% directly from the rates of progress and stoichiometric
% coefficients.

cdot2 = nu_p*qf + nu_r*qr;
creation = [cdot, cdot2, cdot - cdot2]

ddot2 = nu_r*qf + nu_p*qr;
destruction = [ddot, ddot2, ddot - ddot2]

wdot2 = nu_net * qn;
net = [wdot, wdot2, wdot - wdot2]

% 4) Reaction equations

e8    = reactionEqn(g,8)             % equation for reaction 8
e1_10 = reactionEqn(g,1:10)          % equation for rxns 1 - 10
eqs   = reactionEqn(g)               % all equations

% 5) Equilibrium constants

% The equilibrium constants are computed in concentration units,
% with concentrations in kmol/m^3.

kc = equil_Kc(g);
for i = 1:nReactions(g)
disp(sprintf('%50s  %13.5g', eqs{i}, kc(i)))
end

% 6) Multipliers

% For each reaction, a multiplier may be specified that is applied
% to the forward rate coefficient. By default, the multiplier is
% 1.0 for all reactions.

for i = 1:nReactions(g)
setMultiplier(g, i, 2*i);
m = multiplier(g, i);
end

clear all
cleanup
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%