A C++ Thermodynamics Properties Program

In the program below, a gas mixture object is created, and a few thermodynamic properties are computed and printed out.

#include <cantera/Cantera.h>

void thermo_demo(string file, string phase) {
    ThermoPhase* gas = newPhase(file, phase);
    gas->setState_TPX(1500.0, 2.0*OneAtm, "O2:1.0, H2:3.0, AR:1.0");

    // temperature, pressure, and density
    cout << gas->temperature() << endl;
    cout << gas->pressure() << endl;
    cout << gas->density() << endl;

    // molar thermodynamic properties
    cout << gas->enthalpy_mole() << endl;
    cout << gas->entropy_mole() << endl;

    // specific (per unit mass) thermodynamic properties
    cout << gas->enthalpy_mass() << endl;
    cout << gas->entropy_mass() << endl;

    // chemical potentials of the species
    int numSpecies = gas->nSpecies();
    vector_fp mu(numSpecies);
    gas->getChemPotentials(mu.begin());
    int n;
    for (n = 0; n < numSpecies; n++) {
        cout << gas->speciesName(n) << " " << mu[n] << endl;
    }
}
 
int main() {

    try {
        thermo_demo("h2o2.cti","ohmech");
    }
    catch (CanteraError) {
        showErrors();
    }
}

Note that the methods that compute the properties take no input parameters. The properties are computed for the state that has been previously set and stored internally within the object.

Naming Conventions

• methods that return molar properties have names that end in "_mole".
• methods that return properties per unit mass have names that end in "_mass".
• methods that write an array of values into a supplied output array have names that begin with "get". For example, method getChemPotentials(double* mu) writes the species chemical potentials into the output array mu.

The thermodynamic property methods are declared in class ThermoPhase, which is the base class from which all classes that represent any type of phase of matter derive.

See also:

ThermoPhase

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