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Old   June 27, 2010, 05:54
Default Cantera: why happens it?
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Tommaso is on a distinguished road
If I put this code in matlab:
Code:
gas = GRI30;
set(gas,'T',800.0,'P',15*oneatm,'X','H2:0.3971,H2O2:0.397,H2O:0.083,N2:0.032');
r1=Reactor(gas);
a = IdealGasMix('air.cti');
setPressure(a,15*OneAtm);
env = Reservoir(gas);
wall=Wall;
setHeatTransferCoeff(wall,0);
setExpansionRateCoeff(wall, 1.0e6);
setArea(wall, 1.0);
install(wall,r1,env);
sim=ReactorNet({r1});
time=0.0;
dt=0.0001;
tfinal=0.01;
while time < tfinal
p=plot(time,temperature(r1),'go');
set(p,'Color','blue','LineWidth',2)
time = time + dt;
advance(sim,time);
hold on
end
The resulting gas mix is:
Code:
                 H2      0.0802358       0.00945856         -20.7827
                  H      0.0157446      0.000928023         -10.3913
                  O     0.00653354       0.00611286         -15.6992
                 O2      0.0250759        0.0469227         -31.3984
                 OH      0.0550284        0.0547288         -26.0906
                H2O       0.782684         0.824554         -36.4819
                HO2   5.70116e-005      0.000110042         -41.7898
               H2O2   9.74139e-006     1.93767e-005         -52.1811
                  C   1.75036e-035     1.22941e-035         -72.1742
                 CH   7.01569e-036     5.34119e-036         -82.6057
                CH2   1.37287e-035     1.12611e-035         -93.0415
             CH2(S)   1.41046e-036     1.15694e-036         -93.0779
                CH3   3.40071e-035     2.98992e-035         -103.534
                CH4   1.13184e-035     1.06183e-035         -113.926
                 CO   1.75606e-025     2.87642e-025         -87.8635
                CO2   2.25237e-025      5.7967e-025         -103.563
                HCO   2.89359e-030     4.91024e-030         -98.2548
               CH2O   8.71031e-032     1.52942e-031         -108.646
              CH2OH   2.09601e-035     3.80387e-035         -119.052
               CH3O   5.43185e-037     9.85782e-037         -119.068
              CH3OH   1.71918e-036     3.22133e-036         -129.474
                C2H   1.10875e-057     1.62287e-057         -140.852
               C2H2   3.00051e-056     4.56871e-056         -151.193
               C2H3   -1.37201e-057     -2.16995e-057     
               C2H4   -1.60576e-057     -2.63429e-057     
               C2H5   -8.52573e-058     -1.44892e-057     
               C2H6   1.17001e-058     2.05736e-058         -179.221
               HCCO   4.17628e-057     1.00202e-056         -160.984
              CH2CO   -2.51789e-057     -6.1896e-057     
              HCCOH   1.17124e-057      2.8792e-057          -167.55
                  N   1.21541e-006     9.95521e-007          -14.634
                 NH   5.50854e-007     4.83665e-007         -25.0253
                NH2   3.04028e-007     2.84865e-007         -35.4167
                NH3   3.97725e-007     3.96099e-007          -45.808
                NNH   2.72282e-008     4.62093e-008         -39.6593
                 NO     0.00370562       0.00650224         -30.3332
                NO2   2.68585e-006     7.22576e-006         -46.0324
                N2O   1.62991e-007     4.19504e-007         -44.9672
                HNO   1.62198e-006     2.94169e-006         -40.7245
                 CN    5.6591e-034     8.61011e-034         -86.7982
                HCN   2.81108e-032     4.44265e-032         -97.1896
               H2CN   8.23405e-037     1.34985e-036         -107.581
               HCNN   2.61298e-040     6.26982e-040         -111.874
               HCNO   2.60158e-036     6.54562e-036         -112.918
               HOCN   1.55153e-033     3.90369e-033         -112.889
               HNCO   1.15489e-031     2.90571e-031         -112.889
                NCO   1.20418e-032     2.95876e-032         -102.497
                 N2      0.0309188        0.0506502         -29.2679
                 AR              0                0     
               C3H7   5.12899e-079     1.29237e-078         -231.774
               C3H8   1.40577e-079     3.62502e-079         -240.589
             CH2CHO   -3.05942e-058     -7.70116e-058     
             CH3CHO   -1.59432e-056     -4.10718e-056
But if at t=0 there isn't carbonium element, it cannot be never.
I can see that unwanted species have a very low exponent (-30 etc.) but why the result is not zero ?
May be I do something wrong ?

Thank you.
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Old   April 23, 2012, 15:53
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John M.
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Didn't you set initial state mole fractions in .cti file?
Note, your total mole frac. sum, is not equal to 1. See manual, how Cantera works in this case - does it normalize mole fractions?
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