void runexample()
{
// use reaction mechanism GRI-Mech 3.0
IdealGasMix gas("gri30.cti", "gri30");
// create a reservoir for the fuel inlet, and set to pure methane.
Reservoir fuel_in;
gas.setState_TPX(300.0, OneAtm, "CH4:1.0");
fuel_in.insert(gas);
double fuel_mw = gas.meanMolecularWeight();
// create a reservoir for the air inlet
Reservoir air_in;
IdealGasMix air("air.cti");
gas.setState_TPX(300.0, OneAtm, "N2:0.78, O2:0.21, AR:0.01");
double air_mw = air.meanMolecularWeight();
air_in.insert(gas);
// to ignite the fuel/air mixture, we'll introduce a pulse of radicals.
// The steady-state behavior is independent of how we do this, so we'll
// just use a stream of pure atomic hydrogen.
gas.setState_TPX(300.0, OneAtm, "H:1.0");
Reservoir igniter;
igniter.insert(gas);
// create the combustor, and fill it in initially with N2
gas.setState_TPX(300.0, OneAtm, "N2:1.0");
Reactor combustor;
combustor.insert(gas);
combustor.setInitialVolume(1.0);
// create a reservoir for the exhaust. The initial composition
// doesn't matter.
Reservoir exhaust;
exhaust.insert(gas);
// lean combustion, phi = 0.5
double equiv_ratio = 0.5;
// compute fuel and air mass flow rates
double factor = 0.1;
double air_mdot = factor*9.52*air_mw;
double fuel_mdot = factor*equiv_ratio*fuel_mw;
// create and install the mass flow controllers. Controllers
// m1 and m2 provide constant mass flow rates, and m3 provides
// a short Gaussian pulse only to ignite the mixture
MassFlowController m1;
m1.install(fuel_in, combustor);
m1.setMassFlowRate(fuel_mdot);
// Now create the air mass flow controller. Note that this connects
// two reactors with different reaction mechanisms and different
// numbers of species. Downstream and upstream species are matched by
// name.
MassFlowController m2;
m2.install(air_in, combustor);
m2.setMassFlowRate(air_mdot);
// The igniter will use a Gaussian 'functor' object to specify the
// time-dependent igniter mass flow rate.
double A = 0.1;
double FWHM = 0.2;
double t0 = 0.5;
Gaussian igniter_mdot(A, t0, FWHM);
MassFlowController m3;
m3.install(igniter, combustor);
m3.setFunction(&igniter_mdot);
// put a valve on the exhaust line to regulate the pressure
Valve v;
v.install(combustor, exhaust);
double Kv = 1.0;
v.setParameters(1, &Kv);
// the simulation only contains one reactor
ReactorNet sim;
sim.addReactor(combustor);
// take single steps to 6 s, writing the results to a CSV file
// for later plotting.
double tfinal = 1.0;
double tnow = 0.0;
double tres;
std::ofstream f("combustor_cxx.csv");
std::vector<size_t> k_out {
gas.speciesIndex("CH4"),
gas.speciesIndex("O2"),
gas.speciesIndex("CO2"),
gas.speciesIndex("H2O"),
gas.speciesIndex("CO"),
gas.speciesIndex("OH"),
gas.speciesIndex("H"),
gas.speciesIndex("C2H6")
};
while (tnow < tfinal) {
tnow += 0.005;
sim.advance(tnow);
tres = combustor.mass()/v.massFlowRate();
f << tnow << ", "
<< combustor.temperature() << ", "
<< tres << ", ";
ThermoPhase& c = combustor.contents();
for (size_t i = 0; i < k_out.size(); i++) {
f << c.moleFraction(k_out[i]) << ", ";
}
f << std::endl;
}
f.close();
}
int kinetics1(int np, void* p)
{
cout << "Constant-pressure ignition of a "
<< "hydrogen/oxygen/nitrogen"
" mixture \nbeginning at T = 1001 K and P = 1 atm." << endl;
// create an ideal gas mixture that corresponds to GRI-Mech 3.0
IdealGasMix gas("gri30.cti", "gri30");
// set the state
gas.setState_TPX(1001.0, OneAtm, "H2:2.0, O2:1.0, N2:4.0");
int nsp = gas.nSpecies();
// create a reactor
IdealGasConstPressureReactor r;
// 'insert' the gas into the reactor and environment. Note
// that it is ok to insert the same gas object into multiple
// reactors or reservoirs. All this means is that this object
// will be used to evaluate thermodynamic or kinetic
// quantities needed.
r.insert(gas);
double dt = 1.e-5; // interval at which output is written
int nsteps = 100; // number of intervals
// create a 2D array to hold the output variables,
// and store the values for the initial state
Array2D soln(nsp+4, 1);
saveSoln(0, 0.0, gas, soln);
// create a container object to run the simulation
// and add the reactor to it
ReactorNet sim;
sim.addReactor(r);
// main loop
clock_t t0 = clock(); // save start time
for (int i = 1; i <= nsteps; i++) {
double tm = i*dt;
sim.advance(tm);
cout << "time = " << tm << " s" << endl;
saveSoln(tm, gas, soln);
}
clock_t t1 = clock(); // save end time
// make a Tecplot data file and an Excel spreadsheet
std::string plotTitle = "kinetics example 1: constant-pressure ignition";
plotSoln("kin1.dat", "TEC", plotTitle, gas, soln);
plotSoln("kin1.csv", "XL", plotTitle, gas, soln);
// print final temperature and timing data
doublereal tmm = 1.0*(t1 - t0)/CLOCKS_PER_SEC;
cout << " Tfinal = " << r.temperature() << endl;
cout << " time = " << tmm << endl;
cout << " number of residual function evaluations = "
<< sim.integrator().nEvals() << endl;
cout << " time per evaluation = " << tmm/sim.integrator().nEvals()
<< endl << endl;
cout << "Output files:" << endl
<< " kin1.csv (Excel CSV file)" << endl
<< " kin1.dat (Tecplot data file)" << endl;
return 0;
}
int kinetics_example1(int job)
{
try {
cout << "Ignition simulation using class IdealGasMix "
<< "with file gri30.cti."
<< endl;
if (job >= 1) {
cout << "Constant-pressure ignition of a "
<< "hydrogen/oxygen/nitrogen"
" mixture \nbeginning at T = 1001 K and P = 1 atm." << endl;
}
if (job < 2) {
return 0;
}
// create an ideal gas mixture that corresponds to GRI-Mech
// 3.0
IdealGasMix gas("gri30.xml", "gri30");
// set the state
gas.setState_TPX(1001.0, OneAtm, "H2:2.0, O2:1.0, N2:4.0");
size_t kk = gas.nSpecies();
// create a reactor
Reactor r;
// create a reservoir to represent the environment
Reservoir env;
// specify the thermodynamic property and kinetics managers
r.setThermoMgr(gas);
r.setKineticsMgr(gas);
env.setThermoMgr(gas);
// create a flexible, insulating wall between the reactor and the
// environment
Wall w;
w.install(r,env);
// set the "Vdot coefficient" to a large value, in order to
// approach the constant-pressure limit; see the documentation
// for class Reactor
w.setExpansionRateCoeff(1.e9);
w.setArea(1.0);
// create a container object to run the simulation
// and add the reactor to it
ReactorNet sim;
sim.setVerbose(false);
sim.addReactor(r);
double tm;
double dt = 1.e-5; // interval at which output is written
int nsteps = 100; // number of intervals
// create a 2D array to hold the output variables,
// and store the values for the initial state
Array2D soln(kk+4, 1);
saveSoln(0, 0.0, gas, soln);
// main loop
for (int i = 1; i <= nsteps; i++) {
tm = i*dt;
sim.advance(tm);
saveSoln(tm, gas, soln);
}
// make a Tecplot data file and an Excel spreadsheet
string plotTitle = "kinetics example 1: constant-pressure ignition";
plotSoln("kin1.dat", "TEC", plotTitle, gas, soln);
plotSoln("kin1.csv", "XL", plotTitle, gas, soln);
// print final temperature
cout << " Tfinal = " << r.temperature() << endl;
cout << "Output files:" << endl
<< " kin1.csv (Excel CSV file)" << endl
<< " kin1.dat (Tecplot data file)" << endl;
} catch (CanteraError& err) {
// handle exceptions thrown by Cantera
std::cout << err.what() << std::endl;
cout << " terminating... " << endl;
appdelete();
return -1;
}
return 0;
}
