/*******************************************************************
 *  HEADER FILE: define.h - to specify the geometric and           *
 *  operational parameters of a Stirling cycle machine.            *
 *  PROGRAMMER:  izzi urieli                                       *
 *  LAST MODIFICATION DATE:  01/15/97 (included yoke drive)        *
 *******************************************************************/
#ifndef STIRLING
#define STIRLING
#define PI 3.14159265359

/*********  in file "define.c"  ***************************/
/* FUNCTION PROTOTYPES - invoked by function "define"  */
void engine(); /* engine type and working space geometry */
void heatex(); /* heat exchanger geometric parameters */
void gas();    /* working gas properties */
void operat(); /* operating parameters and Schmidt analysis */

/* GLOBAL VARIABLES - specified in function "define" */
FILE *infile;   /*pointer to the input data file */
FILE *outfile;  /*pointer to the output data file */
FILE *printfile;   /*pointer to the print output file */

/*********  in file "gas.c"  ***************************/
/* GLOBAL VARIABLES - specified in function "gas" */
double rgas; /*  gas constant (Joules/kg.K) */
double cp; /* specific heat at const pressure (J/kg.K) */
double cv; /* specific heat at const volume (J/kg.K) */
double gama; /* ratio (cp / cv) */
double mu0; /* dynamic viscosity at ref temp t0 (kg.m/s) */
double t0; /* reference temperature (273 K) */
double t_suth; /* Sutherland constant for dynamic viscosity */
double prandtl; /* Prandtl number (0.71) */

/*********  in file "engine.c"  ***************************/
/* GLOBAL VARIABLES - specified in function "engine" */
char myeng; /* char represents engine type (s sinusodal) */

/* GLOBAL VARIABLES - specified in functions "sinedr", "yokedr" */
double vclc;  /* compression space clearance volumes (cu.m) */
double vcle;  /* expansion space clearance volumes (cu.m) */
double vswc;  /* compression space swept volume (cu.m) */
double vswe;  /* expansion space swept volume (cu.m) */
double alpha; /* expansion space phase angle advance (radians) */

/* GLOBAL VARIABLES - specified in function "yokedr" */
double crank; /* crank radius */
double b1, b2; /* yoke height and base dimensions (m) */
double acomp, aexp; /* area of comp., exp. pistons (m^2) */
double ymin; /* minimum yoke vertical displacement (m) */

/* Should be specified in "engine.c" for loss analysis in  "aploss.c" */
double ddiam; /* diameter of expansion side piston (displacer) (m) */
double dgap; /* displacer cylinder/piston gap (m) */
double xda;  /* expansion (displacer piston) amplitude */

/*********  in file "heatex.c"  ***************************/
/* GLOBAL VARIABLES - specified in function "cooler" */
double vk;   /* vk: cooler void volume (cu.m)   */
double ak;   /* ak: cooler internal free flow area (sq.m) */
double awgk; /* cooler internal wetted area (sq.m) */
double dk;   /* dk: cooler hydraulic diameter (m) */
double lk;   /* lk: cooler effective length (m) */

/* GLOBAL VARIABLES - specified in function "heater" */
double vh;   /*vh:  heater void volume (cu.m)  */
double ah;   /* ah:  heater internal free flow area (sq.m) */
double awgh; /* heater internal wetted area (sq.m) */
double dh;   /* dh:  heater hydraulic diameter (m)  */
double lh;   /* lh:  heater effective length (m)  */

/*********  in file "regen.c"  ***************************/
/* GLOBAL VARIABLES - specified in functions "regen", "matrix" */
double vr;   /* regenerator void volume (cu.m) */
double ar;   /* regenerator internal free flow area (sq.m)   */
double awgr; /* regenerator internal wetted area (sq.m) */
double dr;   /* regenerator hydraulic diameter (m)  */
double lr;   /* regenerator effective length (m)  */
double cmr;  /* regenerator matrix thermal capacity (Joules/K)  */
double cqwr; /* regenerator wall thermal conductance (Watts/K)  */
char rmatrx;  /* specifies the matrix type (foil or mesh) */

/****************  in file "operat.c" ******************/
/* GLOBAL VARIABLES - specified in functions "operat", "schmidt" */
double pmean; /* nominal mean operating pressure (Pa) */
double tk;    /* cold sink operation temperatures */
double th;    /* hot sink operation temperature */
double freq;  /* operating frequency (hertz) */
double tr;    /* effective regenerator temperature (K) */
double omega; /* operating frequency (rads/sec) */
double mgas;  /* mas of gas in system - evaluated by Schmidt */

#endif