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Diffstat (limited to 'Utilib/src/thcond.c')
| -rw-r--r-- | Utilib/src/thcond.c | 102 |
1 files changed, 102 insertions, 0 deletions
diff --git a/Utilib/src/thcond.c b/Utilib/src/thcond.c new file mode 100644 index 0000000..337e8b3 --- /dev/null +++ b/Utilib/src/thcond.c @@ -0,0 +1,102 @@ +/* + freesteam - IAPWS-IF97 steam tables library + Copyright (C) 2004-2009 John Pye + + This program 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. + + This program 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 this program; if not, write to the Free Software + Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. + */ + +/* Appendix B: Recommended Interpolating equation for Industrial Use */ +/* see http://www.iapws.org/relguide/thcond.pdf */ + +#define FREESTEAM_BUILDING_LIB +#include "thcond.h" + +#include <math.h> + +#define THCOND_TSTAR 647.26 +#define THCOND_RHOSTAR 317.7 +#define THCOND_KSTAR 1.0 + +#define THCOND_b0 -0.397070 +#define THCOND_b1 0.400302 +#define THCOND_b2 1.060000 +#define THCOND_B1 -0.171587 +#define THCOND_B2 2.392190 + +#define THCOND_C1 0.642857 +#define THCOND_C2 -4.11717 +#define THCOND_C3 -6.17937 +#define THCOND_C4 0.00308976 +#define THCOND_C5 0.0822994 +#define THCOND_C6 10.0932 + +#define THCOND_d1 0.0701309 +#define THCOND_d2 0.0118520 +#define THCOND_d3 0.00169937 +#define THCOND_d4 -1.0200 + +/* freesteam code */ +double freesteam_k_rhoT(double rho, double T){ + +#define THCOND_a_COUNT 4 + const double THCOND_a[THCOND_a_COUNT] = { + 0.0102811 + ,0.0299621 + ,0.0156146 + ,-0.00422464 + }; + + double DTbar, DTbarpow, Q, S, rhobar18, rhobarQ; + double Tbar = T / THCOND_TSTAR; + double rhobar = rho / THCOND_RHOSTAR; + + /* fast implementation... minimised calls to 'pow' routine... */ + + double Troot = sqrt(Tbar); + double Tpow = Troot; + double lam = 0; + + int k; + for(k = 0; k < THCOND_a_COUNT; ++k) { + lam += THCOND_a[k] * Tpow; + Tpow *= Tbar; + } + + lam += THCOND_b0 + THCOND_b1 * rhobar + THCOND_b2 * exp(THCOND_B1 * SQ(rhobar + THCOND_B2)); + + DTbar = fabs(Tbar - 1) + THCOND_C4; + DTbarpow = pow(DTbar, 3./5); + Q = 2. + THCOND_C5 / DTbarpow; + + if(Tbar >= 1){ + S = 1. / DTbar; + }else{ + S = THCOND_C6 / DTbarpow; + } + + rhobar18 = pow(rhobar, 1.8); + rhobarQ = pow(rhobar, Q); + + lam += + (THCOND_d1 / ipow(Tbar,10) + THCOND_d2) * rhobar18 * + exp(THCOND_C1 * (1 - rhobar * rhobar18)) + + THCOND_d3 * S * rhobarQ * + exp((Q/(1+Q))*(1 - rhobar*rhobarQ)) + + THCOND_d4 * + exp(THCOND_C2 * ipow(Troot,3) + THCOND_C3 / ipow(rhobar,5)); + + return THCOND_KSTAR * lam; +} + |