static Evaluation vaporPressure(const Evaluation& temperature)
{
typedef MathToolbox<Evaluation> Toolbox;
if (temperature > criticalTemperature())
return criticalPressure();
if (temperature < tripleTemperature())
return 0; // N2 is solid: We don't take sublimation into
// account
// note: this is the ancillary equation given on page 1368
const Evaluation& sigma = 1.0 - temperature/criticalTemperature();
const Evaluation& sqrtSigma = Toolbox::sqrt(sigma);
const Scalar N1 = -6.12445284;
const Scalar N2 = 1.26327220;
const Scalar N3 = -0.765910082;
const Scalar N4 = -1.77570564;
return
criticalPressure() *
Toolbox::exp(criticalTemperature()/temperature*
(sigma*(N1 +
sqrtSigma*N2 +
sigma*(sqrtSigma*N3 +
sigma*sigma*sigma*N4))));
}
static Evaluation vaporPressure(const Evaluation& T)
{
typedef Opm::MathToolbox<Evaluation> Toolbox;
if (T > criticalTemperature())
return criticalPressure();
if (T < tripleTemperature())
return 0; // water is solid: We don't take sublimation into account
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
};
Evaluation sigma = T + n[8]/(T - n[9]);
Evaluation A = (sigma + n[0])*sigma + n[1];
Evaluation B = (n[2]*sigma + n[3])*sigma + n[4];
Evaluation C = (n[5]*sigma + n[6])*sigma + n[7];
Evaluation tmp = 2.0*C/(Toolbox::sqrt(B*B - 4.0*A*C) - B);
tmp *= tmp;
tmp *= tmp;
return 1e6*tmp;
}
