Region4.hpp

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// -*- mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
// vi: set et ts=4 sw=4 sts=4:
/*
  This file is part of the Open Porous Media project (OPM).
 
  OPM is free software: you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation, either version 2 of the License, or
  (at your option) any later version.
 
  OPM is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.
 
  You should have received a copy of the GNU General Public License
  along with OPM.  If not, see <http://www.gnu.org/licenses/>.
 
  Consult the COPYING file in the top-level source directory of this
  module for the precise wording of the license and the list of
  copyright holders.
*/
#ifndef OPM_IAPWS_REGION4_HPP
#define OPM_IAPWS_REGION4_HPP
 
#include <opm/material/common/MathToolbox.hpp>
 
#include <cmath>
 
namespace Opm {
namespace IAPWS {

template <class Scalar>
class Region4
{
public:
    template <class Evaluation>
    static Evaluation saturationPressure(const Evaluation& temperature)
    {
        static const Scalar n[10] = {
            0.11670521452767e4, -0.72421316703206e6, -0.17073846940092e2,
            0.12020824702470e5, -0.32325550322333e7, 0.14915108613530e2,
            -0.48232657361591e4, 0.40511340542057e6, -0.23855557567849,
            0.65017534844798e3
        };
 
        const Evaluation& sigma = temperature + n[8]/(temperature - n[9]);
 
        const Evaluation& A = (sigma + n[0])*sigma + n[1];
        const Evaluation& B = (n[2]*sigma + n[3])*sigma + n[4];
        const Evaluation& C = (n[5]*sigma + n[6])*sigma + n[7];
 
        Evaluation tmp = 2*C/(sqrt(B*B - 4*A*C) - B);
        tmp *= tmp;
        tmp *= tmp;
 
        return 1e6*tmp;
    }

    template <class Evaluation>
    static Evaluation vaporTemperature(const Evaluation& pressure)
    {
        static const Scalar n[10] = {
            0.11670521452767e4, -0.72421316703206e6, -0.17073846940092e2,
            0.12020824702470e5, -0.32325550322333e7, 0.14915108613530e2,
            -0.48232657361591e4, 0.40511340542057e6, -0.23855557567849,
            0.65017534844798e3
        };
        const Evaluation& beta = pow((pressure/1e6 /*from Pa to MPa*/), (1./4.));
        const Evaluation& beta2 = pow(beta, 2.);
        const Evaluation& E = beta2 + n[2] * beta + n[5];
        const Evaluation& F = n[0]*beta2 + n[3]*beta + n[6];
        const Evaluation& G = n[1]*beta2 + n[4]*beta + n[7];
 
        const Evaluation& D = ( 2.*G)/(-F -sqrt(pow(F,2.) - 4.*E*G));
 
        const Evaluation& temperature = (n[9] + D - sqrt(pow(n[9]+D , 2.) - 4.* (n[8] + n[9]*D)) ) * 0.5;
 
        return temperature;
    }
};
 
} // namespace IAPWS
} // namespace Opm
 
#endif