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Diffstat (limited to 'Utilib/src/steam_Tx.c')
| -rw-r--r-- | Utilib/src/steam_Tx.c | 140 |
1 files changed, 140 insertions, 0 deletions
diff --git a/Utilib/src/steam_Tx.c b/Utilib/src/steam_Tx.c new file mode 100644 index 0000000..496e4be --- /dev/null +++ b/Utilib/src/steam_Tx.c @@ -0,0 +1,140 @@ +/* +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. +*/ +#define FREESTEAM_BUILDING_LIB +#include "steam_Tx.h" +#include "region.h" +#include "b23.h" +#include "zeroin.h" + +/* .... */ + +#include <stdlib.h> +#include <assert.h> +#include <math.h> + + +int freesteam_bounds_Tx(double T, double x, int verbose){ + +#define BOUND_WARN(MSG) \ + if(verbose){\ + fprintf(stderr,"%s (%s:%d): WARNING " MSG " (T = %g K, x = %g)\n"\ + ,__func__,__FILE__,__LINE__,T,x);\ + } + + if(T <= IAPWS97_TMIN){ + BOUND_WARN("T <= TMIN"); + return 1; + } + if(T > IAPWS97_TCRIT){ + BOUND_WARN("T > TCRIT"); + return 2; + } + + if(x < 0){ + BOUND_WARN("x < 0"); + return 3; + }else if(x > 1){ + BOUND_WARN("x > 1"); + return 4; + } + return 0; +#undef BOUND_WARN +} + +int freesteam_region_Tx(double T, double x){ + if(T >= IAPWS97_TCRIT)return 3; + + if(x <= 0){ + if(T > REGION1_TMAX)return 3; + return 1; + } + + if(x >= 1){ + if(T > REGION1_TMAX)return 3; + return 2; + } + + return 4; +} + +typedef struct{ + double T, s; +} SolveTSData; + +static double Ts_region3_fn(double rho, void *user_data){ +#define D ((SolveTSData *)user_data) + return D->s - freesteam_region3_s_rhoT(rho, D->T); +#undef D +} + +/** + This function will always return saturated mixtures; no negative or >1 + values of x are being 'understood' here (although one can give them meaning + based on extrapolated values of u or h of v, for example...) +*/ +SteamState freesteam_set_Tx(double T, double x){ + SteamState S; + + if(T >= IAPWS97_TCRIT){ + /* region 3 supercritical. just return a state with the specified + temperature and the critical point entropy. arbitrary. */ + double ub, lb, tol, sol, err; + SolveTSData D = {T, freesteam_region3_s_rhoT(IAPWS97_RHOCRIT, IAPWS97_TCRIT)}; + ub = 1./freesteam_region1_v_pT(IAPWS97_PMAX,REGION1_TMAX); + lb = 1./freesteam_region2_v_pT(freesteam_b23_p_T(T),T); + tol = 1e-7; + err = 0; + if(zeroin_solve(&Ts_region3_fn, &D, lb, ub, tol, &sol, &err)){ + fprintf(stderr,"%s (%s:%d): failed to solve for rho\n",__func__,__FILE__,__LINE__); + exit(1); + } + S.region = 3; + S.valueR.R3.T = T; + S.valueR.R3.rho = sol; + }else if(x <= 0){ + if(T > REGION1_TMAX){ + S.region = 3; + S.valueR.R3.T = T; + S.valueR.R3.rho = freesteam_region4_rhof_T(T); + /* FIXME iteratively refine the value */ + }else{ + S.region = 1; + S.valueR.R1.p = freesteam_region4_psat_T(T); + S.valueR.R1.T = T; + } + }else if(x >= 1){ + if(T > REGION1_TMAX){ + S.region = 3; + S.valueR.R3.T = T; + S.valueR.R3.rho = freesteam_region4_rhog_T(T); + /* FIXME iteratively refine the value */ + }else{ + S.region = 2; + S.valueR.R1.p = freesteam_region4_psat_T(T); + S.valueR.R1.T = T; + } + }else{ + /* finally! */ + S.region = 4; + S.valueR.R4.T = T; + S.valueR.R4.x = x; + } + + return S; +} |