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Region4.hpp
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27 #ifndef OPM_IAPWS_REGION4_HPP
28 #define OPM_IAPWS_REGION4_HPP
29 
31 
32 #include <cmath>
33 
34 namespace Opm {
35 namespace IAPWS {
36 
50 template <class Scalar>
51 class Region4
52 {
53 public:
62  template <class Evaluation>
63  static Evaluation saturationPressure(const Evaluation& temperature)
64  {
65  static const Scalar n[10] = {
66  0.11670521452767e4, -0.72421316703206e6, -0.17073846940092e2,
67  0.12020824702470e5, -0.32325550322333e7, 0.14915108613530e2,
68  -0.48232657361591e4, 0.40511340542057e6, -0.23855557567849,
69  0.65017534844798e3
70  };
71 
72  const Evaluation& sigma = temperature + n[8]/(temperature - n[9]);
73 
74  const Evaluation& A = (sigma + n[0])*sigma + n[1];
75  const Evaluation& B = (n[2]*sigma + n[3])*sigma + n[4];
76  const Evaluation& C = (n[5]*sigma + n[6])*sigma + n[7];
77 
78  Evaluation tmp = 2*C/(sqrt(B*B - 4*A*C) - B);
79  tmp *= tmp;
80  tmp *= tmp;
81 
82  return 1e6*tmp;
83  }
84 
93  template <class Evaluation>
94  static Evaluation vaporTemperature(const Evaluation& pressure)
95  {
96  static const Scalar n[10] = {
97  0.11670521452767e4, -0.72421316703206e6, -0.17073846940092e2,
98  0.12020824702470e5, -0.32325550322333e7, 0.14915108613530e2,
99  -0.48232657361591e4, 0.40511340542057e6, -0.23855557567849,
100  0.65017534844798e3
101  };
102  const Evaluation& beta = pow((pressure/1e6 /*from Pa to MPa*/), (1./4.));
103  const Evaluation& beta2 = pow(beta, 2.);
104  const Evaluation& E = beta2 + n[2] * beta + n[5];
105  const Evaluation& F = n[0]*beta2 + n[3]*beta + n[6];
106  const Evaluation& G = n[1]*beta2 + n[4]*beta + n[7];
107 
108  const Evaluation& D = ( 2.*G)/(-F -sqrt(pow(F,2.) - 4.*E*G));
109 
110  const Evaluation& temperature = (n[9] + D - sqrt(pow(n[9]+D , 2.) - 4.* (n[8] + n[9]*D)) ) * 0.5;
111 
112  return temperature;
113  }
114 };
115 
116 } // namespace IAPWS
117 } // namespace Opm
118 
119 #endif
A traits class which provides basic mathematical functions for arbitrary scalar floating point values...
Implements the equations for region 4 of the IAPWS '97 formulation.
Definition: Region4.hpp:52
static Evaluation vaporTemperature(const Evaluation &pressure)
Returns the saturation temperature in of pure water at a given pressure.
Definition: Region4.hpp:94
static Evaluation saturationPressure(const Evaluation &temperature)
Returns the saturation pressure in of pure water at a given temperature.
Definition: Region4.hpp:63