/******************************************************************
* FUNCTION operat - determine operating parameters,               *
*                   do Schmidt analysis                           *
* FILENAME operat.c                                               *
* PROGRAMMER I.Urieli    (FORTRAN)                                *
*            E. Malroy   (C Translation)                          *
* DATE:      03/01/93  (FORTRAN), 02/26/96 (C Translation)        *
* LAST MODIFICATION: 12/24/97 by I.Urieli                         *
* INCLUDE:  <stdio.h>, <math.h>, "define.h"                       *
* GLOBAL VARIABLES:                                               *
*       FILE *infile - pointer to the input data file             *
*       FILE *outfile  - pointer to the output data file          *
*       FILE *printfile - pointer to the print output file        *
*       pmean: nominal mean operating pressure (Pa)               *
*       omega: operating frequency (rads/sec)                     *
*       freq: operating frequency (herz)                          *
*       tk: cold sink temperature (K)                             *
*       th: hot source temperature (K)                            *
*       tr: effective regenerator temperature (K)                 *
* SYMBOLIC CONSTANTS: PI 3.14159265359                            *
* PROTOTYPE: void operat(void);                                   *
* PRE:  infile, outfile, printfile                                *
* POST:  pmean, tk, th, freq, tr, omega have been specified       *
*        Schmidt analysis done, mgas determined.                  *
******************************************************************/
#include <stdio.h>
#include <math.h>
#include "define.h"

void schmidt(void); /* Schmidt analysis, determine mgas */

void operat(void)
{

   double dqwr; /* regenerator wall heat leakage(Watts)  */

   printf("\n enter mean pres(Pa), tk, th(K), freq(Hz)\n");
   fscanf(infile, "%lf %lf %lf %lf", &pmean,&tk,&th,&freq);
   fprintf(outfile,"  %e  %.1f  %.1f  %.1f\n", pmean,tk,th,freq);
   fprintf(printfile," mean pres(Pa), tk, th(K), freq(Hz):\n");
   fprintf(printfile,"    %e %.1f %.1f %.1f\n", pmean,tk,th,freq);
   tr = (th - tk)/log(th/tk);
   printf("effective regenerator temperature (K): %.1f\n",tr);
   fprintf(printfile,"effective regenerator temperature (K): %.1f\n",tr);
   omega = 2.0*PI*freq;

   schmidt();

/*     ***regenerator wall heat loss                     */
   dqwr = cqwr*(th - tk);
   printf(" regen. wall heat leakage(Watts) %.1f\n", dqwr);
   fprintf(printfile," regen. wall heat leakage(Watts) %.1f\n", dqwr);
}

/******************************************************************
* FUNCTION schmidt - evaluate total mas of working gas (mgas),    *
*       Schmidt analysis of the system                            *
* FILENAME operat.c                                               *
* PROGRAMMER I.Urieli    (FORTRAN)                                *
*            E. Malroy   (C Translation)                          *
* DATE:      03/01/93  (FORTRAN), 02/26/96 (C Translation)        *
* LAST MODIFICATION: 12/24/97 by I.Urieli                         *
* INCLUDE:  <stdio.h>, <math.h>, "define.h"                       *
* GLOBAL VARIABLES:                                               *
*       FILE *printfile - pointer to the print output file        *
*       vclc: compression clearance volume (cu.m)                 *
*       vcle: expansion clearance volume (cu.m)                   *
*       vswc: compression swept volume (cu.m)                     *
*       vswe: expansion swept volume (cu.m)                       *
*       alpha: expansion space phase angle advance (radians)      *
*       vk: cooler void volume (cu.m)                             *
*       vr: regenerator void volume (cu.m)                        *
*       vh: heater void volume (cu.m)                             *
*       rgas: gas constant (Joules/kg.K)                          *
*       pmean: nominal mean operating pressure (Pa)               *
*       freq: operating frequency (herz)                          *
*       tk: cold sink operating temperatures                      *
*       th: hot sink operating temperatures                       *
*       tr: effective regenerator temperature (K)                 *
*       mgas: mass of working gas in the system (kg)              *
* SYMBOLIC CONSTANTS: PI 3.14159265359                            *
* PROTOTYPE: void schmidt(void);                                  *
* PRE:  vswc, vswe, vclc, vcle, alpha (engine volumes, phase)     *
*       vk, vr, vh (heat exchanger void volumes)                  *
*       rgas (working gas constant)                               *
*       tk, tr, th, pmean, freq  (operational parameters)         *
* POST:  mgas has been determined                                 *
*        Schmidt analysis results have been output                *
******************************************************************/

void schmidt(void)
{
   double c, s, b, sqrtb, bf, beta, /* Schmidt analysis parameters */
          w, wc, we, /* work done (Joules/cycle) total, comp, exp */
          power, eff; /* power (Watts), thermal efficiency */

   c = sqrt(pow((vswe/th),2.0) + pow((vswc/tk),2.0)
               + 2.0*(vswe/th)*(vswc/tk)*cos(alpha))/2.0;
   s = (vswc/2.0 + vclc + vk)/tk + vr/tr
                 + (vswe/2.0 + vcle + vh)/th;
   b = c/s;
   sqrtb = sqrt(1.0 - b*b);
   bf = (1.0 - 1.0/sqrtb);
   beta = atan(vswe*sin(alpha)/th/
         (vswe*cos(alpha)/th + vswc/tk));

   /***total mass of working gas in machine   */
   mgas = pmean*s*sqrtb/rgas;
   printf(" Total mass of gas (gm) %.3f",mgas*1.0e3);
   fprintf(printfile," Total mass of gas (gm) %.3f",mgas*1.0e3);

   /***work output */
   wc = PI*vswc*mgas*rgas*sin(beta)*bf/c;
   we = PI*vswe*mgas*rgas*sin(beta - alpha)*bf/c;
   w = wc + we;
   power = w*freq;
   eff = w/we;

   printf("\n Schmidt analysis\n");
   printf(" Work(joules) %.1f,  Power(watts) %.1f\n", w,power);
   printf(" Qexp(joules) %.1f,  Qcom(joules) %.1f\n", we,wc);
   printf(" indicated efficiency %.3f\n", eff);
   fprintf(printfile,"\nSchmidt analysis\n");
   fprintf(printfile," Work(joules) %.1f, Power(watts) %.1f\n", w,power);
   fprintf(printfile," Qexp(joules) %.1f, Qcom(joules) %.1f\n", we,wc);
   fprintf(printfile," indicated efficiency %.3f\n", eff);
}