1  /******************************************************************
     2  * FUNCTION operat - determine operating parameters,               *
     3  *                   do Schmidt analysis                           *
     4  * FILENAME operat.c                                               *
     5  * PROGRAMMER I.Urieli    (FORTRAN)                                *
     6  *            E. Malroy   (C Translation)                          *
     7  * DATE:      03/01/93  (FORTRAN), 02/26/96 (C Translation)        *
     8  * LAST MODIFICATION: 12/24/97 by I.Urieli                         *
     9  * INCLUDE:  <stdio.h>, <math.h>, "define.h"                       *
    10  * GLOBAL VARIABLES:                                               *
    11  *       FILE *infile - pointer to the input data file             *
    12  *       FILE *outfile  - pointer to the output data file          *
    13  *       FILE *printfile - pointer to the print output file        *
    14  *       pmean: nominal mean operating pressure (Pa)               *
    15  *       omega: operating frequency (rads/sec)                     *
    16  *       freq: operating frequency (herz)                          *
    17  *       tk: cold sink temperature (K)                             *
    18  *       th: hot source temperature (K)                            *
    19  *       tr: effective regenerator temperature (K)                 *
    20  * SYMBOLIC CONSTANTS: PI 3.14159265359                            *
    21  * PROTOTYPE: void operat(void);                                   *
    22  * PRE:  infile, outfile, printfile                                *
    23  * POST:  pmean, tk, th, freq, tr, omega have been specified       *
    24  *        Schmidt analysis done, mgas determined.                  *
    25  ******************************************************************/
    26  #include <stdio.h>
    27  #include <math.h>
    28  #include "define.h"
    29  
    30  void schmidt(void); /* Schmidt analysis, determine mgas */
    31  
    32  void operat(void)
    33  {
    34  
    35     double dqwr; /* regenerator wall heat leakage(Watts)  */
    36  
    37     printf("\n enter mean pres(Pa), tk, th(K), freq(Hz)\n");
    38     fscanf(infile, "%lf %lf %lf %lf", &pmean,&tk,&th,&freq);
    39     fprintf(outfile,"  %e  %.1f  %.1f  %.1f\n", pmean,tk,th,freq);
    40     fprintf(printfile," mean pres(Pa), tk, th(K), freq(Hz):\n");
    41     fprintf(printfile,"    %e %.1f %.1f %.1f\n", pmean,tk,th,freq);
    42     tr = (th - tk)/log(th/tk);
    43     printf("effective regenerator temperature (K): %.1f\n",tr);
    44     fprintf(printfile,"effective regenerator temperature (K): %.1f\n",tr);
    45     omega = 2.0*PI*freq;
    46  
    47     schmidt();
    48  
    49  /*     ***regenerator wall heat loss                     */
    50     dqwr = cqwr*(th - tk);
    51     printf(" regen. wall heat leakage(Watts) %.1f\n", dqwr);
    52     fprintf(printfile," regen. wall heat leakage(Watts) %.1f\n", dqwr);
    53  }
    54  
    55  /******************************************************************
    56  * FUNCTION schmidt - evaluate total mas of working gas (mgas),    *
    57  *       Schmidt analysis of the system                            *     
    58  * FILENAME operat.c                                               *
    59  * PROGRAMMER I.Urieli    (FORTRAN)                                *
    60  *            E. Malroy   (C Translation)                          *
    61  * DATE:      03/01/93  (FORTRAN), 02/26/96 (C Translation)        *
    62  * LAST MODIFICATION: 12/24/97 by I.Urieli                         *
    63  * INCLUDE:  <stdio.h>, <math.h>, "define.h"                       *
    64  * GLOBAL VARIABLES:                                               *
    65  *       FILE *printfile - pointer to the print output file        *
    66  *       vclc: compression clearance volume (cu.m)                 *
    67  *       vcle: expansion clearance volume (cu.m)                   *
    68  *       vswc: compression swept volume (cu.m)                     *
    69  *       vswe: expansion swept volume (cu.m)                       *
    70  *       alpha: expansion space phase angle advance (radians)      *
    71  *       vk: cooler void volume (cu.m)                             *
    72  *       vr: regenerator void volume (cu.m)                        *
    73  *       vh: heater void volume (cu.m)                             *
    74  *       rgas: gas constant (Joules/kg.K)                          *
    75  *       pmean: nominal mean operating pressure (Pa)               *
    76  *       freq: operating frequency (herz)                          *
    77  *       tk: cold sink operating temperatures                      *
    78  *       th: hot sink operating temperatures                       *
    79  *       tr: effective regenerator temperature (K)                 *
    80  *       mgas: mass of working gas in the system (kg)              *
    81  * SYMBOLIC CONSTANTS: PI 3.14159265359                            *
    82  * PROTOTYPE: void schmidt(void);                                  *
    83  * PRE:  vswc, vswe, vclc, vcle, alpha (engine volumes, phase)     *
    84  *       vk, vr, vh (heat exchanger void volumes)                  *
    85  *       rgas (working gas constant)                               *
    86  *       tk, tr, th, pmean, freq  (operational parameters)         *
    87  * POST:  mgas has been determined                                 *
    88  *        Schmidt analysis results have been output                *
    89  ******************************************************************/
    90  
    91  void schmidt(void)
    92  {
    93     double c, s, b, sqrtb, bf, beta, /* Schmidt analysis parameters */
    94            w, wc, we, /* work done (Joules/cycle) total, comp, exp */
    95            power, eff; /* power (Watts), thermal efficiency */
    96  
    97     c = sqrt(pow((vswe/th),2.0) + pow((vswc/tk),2.0)
    98                 + 2.0*(vswe/th)*(vswc/tk)*cos(alpha))/2.0;
    99     s = (vswc/2.0 + vclc + vk)/tk + vr/tr
   100                   + (vswe/2.0 + vcle + vh)/th;
   101     b = c/s;
   102     sqrtb = sqrt(1.0 - b*b);
   103     bf = (1.0 - 1.0/sqrtb);
   104     beta = atan(vswe*sin(alpha)/th/
   105           (vswe*cos(alpha)/th + vswc/tk));
   106  
   107     /***total mass of working gas in machine   */
   108     mgas = pmean*s*sqrtb/rgas;
   109     printf(" Total mass of gas (gm) %.3f",mgas*1.0e3);
   110     fprintf(printfile," Total mass of gas (gm) %.3f",mgas*1.0e3);
   111  
   112     /***work output */
   113     wc = PI*vswc*mgas*rgas*sin(beta)*bf/c;
   114     we = PI*vswe*mgas*rgas*sin(beta - alpha)*bf/c;
   115     w = wc + we;
   116     power = w*freq;
   117     eff = w/we;
   118  
   119     printf("\n Schmidt analysis\n");
   120     printf(" Work(joules) %.1f,  Power(watts) %.1f\n", w,power);
   121     printf(" Qexp(joules) %.1f,  Qcom(joules) %.1f\n", we,wc);
   122     printf(" indicated efficiency %.3f\n", eff);
   123     fprintf(printfile,"\nSchmidt analysis\n");
   124     fprintf(printfile," Work(joules) %.1f, Power(watts) %.1f\n", w,power);
   125     fprintf(printfile," Qexp(joules) %.1f, Qcom(joules) %.1f\n", we,wc);
   126     fprintf(printfile," indicated efficiency %.3f\n", eff);
   127  }
condor{t.gentry}18: