ch4.hh

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#ifndef DUMUX_CH4_HH
#define DUMUX_CH4_HH
 
#include <dumux/material/idealgas.hh>
 
#include <cmath>
 
#include <dumux/material/components/base.hh>
#include <dumux/material/components/gas.hh>
 
namespace Dumux {
namespace Components {

template <class Scalar>
class CH4
: public Components::Base<Scalar, CH4<Scalar> >
, public Components::Gas<Scalar, CH4<Scalar> >
{
    using IdealGas = Dumux::IdealGas<Scalar>;
 
public:
    static std::string name()
    { return "CH4"; }

    static constexpr Scalar molarMass()
    { return 16.043e-3; /* [kg/mol] */}

    static Scalar criticalTemperature()
    { return 190.4; /* [K] */ }

    static Scalar criticalPressure()
    { return 46e5; /* [Pa] */ }

    static Scalar tripleTemperature()
    { return 90.7; /* [K] */ }

    static Scalar triplePressure()
    { return 0; /* [Pa] */ }

    static Scalar vaporPressure(Scalar T)
    { DUNE_THROW(Dune::NotImplemented, "vaporPressure for CH4"); }

    static constexpr bool gasIsCompressible()
    { return true; }

    static Scalar gasDensity(Scalar temperature, Scalar pressure)
    {
        // Assume an ideal gas
        return IdealGas::density(molarMass(), temperature, pressure);
    }

    static Scalar gasMolarDensity(Scalar temperature, Scalar pressure)
    { return IdealGas::molarDensity(temperature, pressure); }

    static constexpr bool gasIsIdeal()
    { return true; }

    static Scalar gasPressure(Scalar temperature, Scalar density)
    {
        // Assume an ideal gas
        return IdealGas::pressure(temperature, density/molarMass());
    }

    static const Scalar gasEnthalpy(Scalar temperature,
                                    Scalar pressure)
    {
        return gasHeatCapacity(temperature, pressure) * temperature;
    }

    static Scalar gasHeatCapacity(Scalar T,
                                  Scalar pressure)
    {
        // method of Joback
        const Scalar cpVapA = 19.25;
        const Scalar cpVapB = 0.05213;
        const Scalar cpVapC = 1.197e-5;
        const Scalar cpVapD = -1.132e-8;
 
        return
            1/molarMass()* // conversion from [J/(mol*K)] to [J/(kg*K)]
            (cpVapA + T*
              (cpVapB/2 + T*
                (cpVapC/3 + T*
                  (cpVapD/4))));
    }

    static const Scalar gasInternalEnergy(Scalar temperature,
                                          Scalar pressure)
    {
 
        return
            gasEnthalpy(temperature, pressure) -
            1/molarMass()* // conversion from [J/(mol K)] to [J/(kg K)]
            IdealGas::R*temperature; // = pressure * spec. volume for an ideal gas
    }

    static Scalar gasViscosity(Scalar temperature, Scalar pressure)
    {
        const Scalar Tc = criticalTemperature();
        const Scalar Vc = 98.6; // critical specific volume [cm^3/mol]
        const Scalar omega = 0.011; // accentric factor
        const Scalar M = molarMass() * 1e3; // molar mas [g/mol]
        const Scalar dipole = 0.0; // dipole moment [debye]
 
        using std::sqrt;
        Scalar mu_r4 = 131.3 * dipole / sqrt(Vc * Tc);
        mu_r4 *= mu_r4;
        mu_r4 *= mu_r4;
 
        using std::exp;
        using std::pow;
        Scalar Fc = 1 - 0.2756*omega + 0.059035*mu_r4;
        Scalar Tstar = 1.2593 * temperature/Tc;
        Scalar Omega_v =
            1.16145*pow(Tstar, -0.14874) +
            0.52487*exp(- 0.77320*Tstar) +
            2.16178*exp(- 2.43787*Tstar);
        Scalar mu = 40.785*Fc*sqrt(M*temperature)/(pow(Vc, 2./3)*Omega_v);
 
        // conversion from micro poise to Pa s
        return mu/1e6 / 10;
    }
};
 
} // end namespace Components
 
} // end namespace Dumux
 
#endif