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/* |
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ASCEND modelling environment |
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Copyright (C) 2004-2010 John Pye |
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|
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This program is free software; you can redistribute it and/or |
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modify it under the terms of the GNU General Public License |
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as published by the Free Software Foundation; either version 2 |
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of the License, or (at your option) any later version. |
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|
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This program is distributed in the hope that it will be useful, |
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but WITHOUT ANY WARRANTY; without even the implied warranty of |
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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GNU General Public License for more details. |
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|
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You should have received a copy of the GNU General Public License |
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along with this program. If not, see <http://www.gnu.org/licenses/>. |
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*/ |
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|
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#include "solve_ph.h" |
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#include "fprops.h" |
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#include "sat.h" |
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#include "derivs.h" |
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#include "rundata.h" |
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|
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#include <stdio.h> |
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#include <math.h> |
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#include <stdlib.h> |
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|
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#define SOLVE_PH_DEBUG |
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#define SOLVE_PH_ERRORS |
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|
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//#define FPE_DEBUG |
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//#define ASSERT_DEBUG |
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|
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#ifdef ASSERT_DEBUG |
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# include <assert.h> |
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#else |
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# define assert(ARGS...) |
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#endif |
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|
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#include <setjmp.h> |
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#include <signal.h> |
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|
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#ifdef FPE_DEBUG |
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#define _GNU_SOURCE |
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#include <fenv.h> |
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int feenableexcept(int excepts); |
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int fedisableexcept(int excepts); |
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int fegetexcept(void); |
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#endif |
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|
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#ifdef SOLVE_PH_DEBUG |
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# include "color.h" |
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# define MSG(FMT, ...) \ |
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color_on(stderr,ASC_FG_BRIGHTRED);\ |
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fprintf(stderr,"%s:%d: ",__FILE__,__LINE__);\ |
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color_on(stderr,ASC_FG_BRIGHTBLUE);\ |
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fprintf(stderr,"%s: ",__func__);\ |
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color_off(stderr);\ |
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fprintf(stderr,FMT "\n",##__VA_ARGS__) |
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#else |
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# define MSG(ARGS...) ((void)0) |
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#endif |
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|
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#ifdef SOLVE_PH_ERRORS |
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# include "color.h" |
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# define ERRMSG(STR,...) \ |
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color_on(stderr,ASC_FG_BRIGHTRED);\ |
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fprintf(stderr,"ERROR:");\ |
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color_off(stderr);\ |
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fprintf(stderr," %s:%d:" STR "\n", __func__, __LINE__ ,##__VA_ARGS__) |
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#else |
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# define ERRMSG(ARGS...) ((void)0) |
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#endif |
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|
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int fprops_region_ph(double p, double h, const PureFluid *fluid, FpropsError *err){ |
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double Tsat, rhof, rhog; |
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double p_c = fluid->data->p_c; |
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|
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if(p >= p_c)return FPROPS_NON; |
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|
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fprops_sat_p(p, &Tsat, &rhof, &rhog, fluid, err); |
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if(*err){ |
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*err = FPROPS_SAT_CVGC_ERROR; |
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return FPROPS_ERROR; |
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} |
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|
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double hf = fluid->h_fn(Tsat, rhof, fluid->data, err); |
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if(h <= hf)return FPROPS_NON; |
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|
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double hg = fluid->h_fn(Tsat,rhog, fluid->data, err); |
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if(h >= hg)return FPROPS_NON; |
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|
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return FPROPS_SAT; |
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} |
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|
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typedef void SignalHandler(int); |
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|
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#ifdef FPE_DEBUG |
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jmp_buf mark; |
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void fprops_fpe(int sig){ |
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MSG("Catching signal %d!",sig); |
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feclearexcept(FE_DIVBYZERO|FE_INVALID|FE_OVERFLOW); |
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longjmp(mark, -1); |
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} |
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#endif |
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|
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void fprops_solve_ph(double p, double h, double *T, double *rho, int use_guess |
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, const PureFluid *fluid, FpropsError *err |
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){ |
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double Tsat, rhof, rhog, hf, hg; |
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double T1, rho1; |
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int subcrit_pressure = 0; |
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int liquid_iteration = 0; |
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double rhof_t; |
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double p_c = fluid->data->p_c; |
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|
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MSG("Solving for p=%f bar, h=%f kJ/kgK (EOS type %d, '%s')",p/1e5,h/1e3,fluid->type,fluid->name); |
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|
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#ifdef FPE_DEBUG |
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feenableexcept(FE_DIVBYZERO | FE_INVALID | FE_OVERFLOW); |
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SignalHandler *old = signal(SIGFPE,&fprops_fpe); |
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(void)old;/* not used for anything at this stage */ |
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int jmpret = setjmp(mark); |
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if(jmpret==0){ |
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#endif |
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MSG("p_c = %f bar",p_c/1e5); |
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if(p < p_c){ |
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/* TODO what about testing for p >= p_t? */ |
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MSG("Calculate saturation Tsat(p < p_c) with p = %f",p); |
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fprops_sat_p(p, &Tsat, &rhof, &rhog, fluid, err); |
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if(*err){ |
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ERRMSG("Unable to solve saturation state"); |
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*err = FPROPS_SAT_CVGC_ERROR; |
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return; |
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} |
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hf = fluid->h_fn(Tsat, rhof, fluid->data, err); |
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hg = fluid->h_fn(Tsat, rhog, fluid->data, err); |
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MSG("at p = %f bar, T_sat = %f, rhof = %f, hf = %f kJ/kg, hg = %f",p/1e5,Tsat,rhof, hf/1e3,hg/1e3); |
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|
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if(hf <= h && h <= hg){ |
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MSG("SATURATION REGION"); |
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/* saturation region... easy */ |
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double x = (h - hf)/(hg - hf); |
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*rho = 1./(x/rhog + (1.-x)/rhof); |
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*T = Tsat; |
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return; |
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} |
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|
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subcrit_pressure = 1; |
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if(h < hf){ |
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liquid_iteration = 1; |
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if(!use_guess){ |
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*T = Tsat; |
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*rho = rhof; |
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MSG("h < hf; LIQUID GUESS: T = %f, rho = %f",*T, *rho); |
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} |
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}else if(!use_guess){ |
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*T = 1.1 * Tsat; |
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*rho = rhog * 0.5; |
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MSG("GAS GUESS: T = %f, rho = %f",*T, *rho); |
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} |
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}else{ /* p >= p_c */ |
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/* FIXME: still some problems here at very high pressures */ |
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if(!use_guess){ |
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/* FIXME we should cache/precalculate hc, store in rundata. */ |
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double hc = fluid->h_fn(fluid->data->T_c, fluid->data->rho_c, fluid->data, err); |
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assert(!isnan(hc)); |
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MSG("hc = %f kJ/kgK",hc/1e3); |
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if(h < 0.8*hc){ /* FIXME should make use of h_ref here in some way? Otherwise arbitrary... */ |
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#if 0 |
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double Tsat1, psat1, rhof1, rhog1; |
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int res = fprops_sat_p(p, &Tsat1, &rhof1, &rhog1, fluid); |
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MSG("Unable to solve saturation at p = %f",p); |
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*T = Tsat1; |
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*rho = rhof1; |
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#else |
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MSG("h < 0.9 hc... using saturation Tsat(hf) for starting guess"); |
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double Tsat1, psat1, rhof1, rhog1; |
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fprops_sat_hf(h, &Tsat1, &psat1, &rhof1, &rhog1, fluid, err); |
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if(*err){ |
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MSG("Unable to solve Tsat(hf)"); |
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/* accuracy of the estimate of Tsat(hf) doesn't matter |
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very much so we can ignore this error. */ |
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|
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/* try initialising to T_t, rho_f(T_t) */ |
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Tsat1 = fluid->data->T_t; |
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MSG("T_t = %f",Tsat1); |
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fprops_sat_T(Tsat1, &psat1, &rhof1, &rhog1, fluid, err); |
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if(*err)MSG("Unable to solve rhof(Tt)"); |
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} |
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*T = Tsat1; |
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*rho = rhof1; |
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#endif |
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}else{ |
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*T = fluid->data->T_c * 1.01; |
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*rho = fluid->data->rho_c * 1.05; |
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} |
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MSG("SUPERCRITICAL GUESS: T = %f, rho = %f", *T, *rho); |
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} |
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} |
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|
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MSG("STARTING NON-SAT ITERATION"); |
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//*rho = 976.82687191126922; |
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//*T = 344.80371310850518; |
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|
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T1 = *T; |
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rho1 = *rho; |
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assert(!isnan(T1)); |
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assert(!isnan(rho1)); |
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|
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if(liquid_iteration){ |
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double pt,rhogt; |
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fprops_triple_point(&pt, &rhof_t, &rhogt, fluid, err); |
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if(*err){ |
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ERRMSG("Unable to solve triple point liquid density."); |
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*err = FPROPS_SAT_CVGC_ERROR; |
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return; |
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} |
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} |
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|
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/* try our own home-baked newton iteration */ |
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int i = 0; |
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*err = FPROPS_NO_ERROR; |
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double delta_T = 0; |
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double delta_rho = 0; |
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MSG("STARTING ITERATION"); |
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MSG("rhof_t = %f",rhof_t); |
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while(i++ < 200){ |
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double p1 = fluid->p_fn(T1,rho1, fluid->data, err); |
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if(*err){ |
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MSG("Got an error ('%s') in p_fn calculation",fprops_error(*err)); |
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} |
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double h1 = fluid->h_fn(T1,rho1, fluid->data, err); |
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assert(!isnan(h1)); |
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|
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if(i >= 2){ |
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int nred = 10; |
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while(p1 <= 0 && nred){ |
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rho1 = rho1 - delta_rho; |
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T1 = T1 - delta_T; |
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delta_rho *= 0.5; |
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delta_T *= 0.5; |
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rho1 = rho1 + delta_rho; |
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T1 = T1 + delta_T; |
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p1 = fluid->p_fn(T1,rho1,fluid->data, err); |
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MSG("Set smaller step as p < 0. T1 = %f, rho1 = %f --> p1 = %f",T1, rho1, p1); |
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nred--; |
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} |
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} |
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|
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MSG(" %d: T = %f, rho = %f\tp = %f bar, h = %f kJ/kg", i, T1, rho1, p1/1e5, h1/1e3); |
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//MSG(" p error = %f bar",(p1 - p)/1e5); |
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//MSG(" h error = %f kJ/kg",(h1 - h)/1e3); |
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|
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if(p1 < 0){ |
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MSG("p1 < 0, reducing dT, drho"); |
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T1 -= (delta_T *= 0.5); |
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rho1 -= (delta_rho *= 0.5); |
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continue; |
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} |
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|
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if(fabs(p1 - p) < 1e-4 && fabs(h1 - h) < 1e-8){ |
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MSG("Converged to T = %f, rho = %f, in homebaked Newton solver", T1, rho1); |
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*T = T1; |
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*rho = rho1; |
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return; |
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} |
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/* calculate step, we're solving log(p1) in this code... */ |
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double f = log(p1) - log(p); |
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double g = h1 - h; |
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assert(!isnan(f)); |
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assert(!isnan(g)); |
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assert(rho1 != 0); |
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assert(p1 != 0); |
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assert(!isnan(fprops_non_dZdT_v('p', T1,rho1, fluid,err))); |
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double f_T = 1./p1 * fprops_non_dZdT_v('p', T1,rho1, fluid,err); |
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double f_rho = -1./p1/SQ(rho1) * fprops_non_dZdv_T('p', T1, rho1, fluid,err); |
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double g_T = fprops_non_dZdT_v('h', T1,rho1, fluid,err); |
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double g_rho = -1./SQ(rho1) * fprops_non_dZdv_T('h', T1, rho1, fluid,err); |
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assert(!isnan(f_T)); |
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|
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if(isnan(f_rho)){ |
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ERRMSG(" rho1 = %f, T1 = %f",rho1, T1); |
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} |
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assert(!isnan(f_rho)); |
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|
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assert(!isnan(g_T)); |
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assert(!isnan(g_rho)); |
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|
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double det = g_rho * f_T - f_rho * g_T; |
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assert(det!=0); |
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assert(!isnan(det)); |
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MSG(" df/dT = %e\t\tdf/drho = %e",f_T, f_rho); |
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MSG(" dg/dT = %e\t\tdg/drho = %e",g_T, g_rho); |
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|
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delta_T = -1./det * (g_rho * f - f_rho * g); |
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delta_rho = -1./det * (f_T * g - g_T * f); |
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assert(!isnan(delta_T)); |
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assert(!isnan(delta_rho)); |
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MSG(" dT = %f", delta_T); |
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MSG(" drho = %f", delta_rho); |
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|
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if(subcrit_pressure){ |
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if(h > hg){ |
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/* vapour */ |
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int i = 0; |
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while(rho1 + delta_rho > rhog && i++ < 20){ |
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delta_rho *= 0.5; |
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} |
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}else{ |
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/* liquid */ |
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while(rho1 + delta_rho < rhof && i++ < 20){ |
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delta_rho *= 0.5; |
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} |
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if(T1 + delta_T < fluid->data->T_t) delta_T = 0.5 * (T1 + fluid->data->T_t); |
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} |
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}else{ |
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#if 0 |
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/* supercritical... stay above critical temperature of density > rho_crit */ |
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if(rho1 + delta_rho > fluid->data->rho_c && T1 + delta_T < fluid->data->T_c){ |
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delta_T = 0.5 *(T1 + fluid->data->T_c); |
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} |
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#endif |
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} |
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/* don't go too dense */ |
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#if 1 |
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if(liquid_iteration){ |
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MSG("rho1 = %f, delta_rho = %f, rho1+delta_rho = %f", rho1, delta_rho, rho1+delta_rho); |
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if(rho1 + delta_rho > rhof_t){ |
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MSG("Limit rho to be less than rhof_t"); |
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delta_rho = rhof_t - rho1; |
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} |
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} |
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#endif |
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|
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/* don't go too hot */ |
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if(T1 + delta_T > 5000) delta_T = 5000 - T1; |
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|
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/* avoid huge step */ |
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while(fabs(delta_T / T1) > 0.7){ |
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MSG("Reduce delta_T"); |
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delta_T *= 0.5; |
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} |
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|
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/* NOTE if step limit is less than 0.5, we're getting errors */ |
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while(fabs(delta_rho / rho1) > 0.7){ |
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MSG("Reduce delta_rho"); |
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delta_rho *= 0.5; |
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} |
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|
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T1 = T1 + delta_T; |
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if(T1 < fluid->data->T_t)T1 = fluid->data->T_t; |
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rho1 = rho1 + delta_rho; |
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} |
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#ifdef FPE_DEBUG |
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}else{ |
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/* an FPE occurred */ |
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MSG("An FPE occurred"); |
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abort(); |
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} |
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#endif |
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|
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*T = T1; |
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*rho = rho1; |
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ERRMSG("Iteration failed for '%s' with p = %.12e, h = %.12e",fluid->name, p,h); |
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*err = FPROPS_NUMERIC_ERROR; |
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return; |
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|
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#if 0 |
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int res = fprops_nonsolver('p','h',p,h,T,rho,fluid); |
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ERRMSG("Iteration failed in nonsolver"); |
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return res; |
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#endif |
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} |
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