/******************************************************************
* FUNCTION: reynum - evaluates dynamic viscosity and Reynolds     *
*           number                                                *
* FILENAME reynum.c                                               *
* PROGRAMMER I.Urieli    (FORTRAN)                                *
*            E. Malroy   (C Translation)                          *
* DATE:      12/01/94  (FORTRAN), 06/15/96 (C Translation)        *
* LAST MODIFICATION:  08/22/96  Eric Malroy                       *
* INCLUDE:  <stdio.h>, <math.h>, "define.h"                       *
* GLOBAL VARIABLES:                                               *
*    rgas   - gas constant (Joules/kg.K)                          *
*    cp     - specific heat at const pressure (J/kg.K)            *
*    cv     - specific heat at const volume (J/kg.K)              *
*    gamma  - ratio (cp / cv)                                     *
*    mu0    - dynamic viscosity at ref temp t0 (kg.m/s)           *
*    t0     - reference temperature (273 K)                       *
*    t_suth    - Sutherland constant for dynamic viscosity        *
*    prandt - Prandtl number (0.71)                               *
* PROTOTYPES:                                                     *
*    void reynum(double,double,double,double *,double *,double *) *
* PRE:   mu0, t0, t_suth, cp, prandt                              *
* POST:  *pt_re, *pt_kgas, *pt_mu have been fully determined      *
******************************************************************/
#include <stdio.h>
#include <math.h>
#include "define.h"
#include "adiabatic.h"

void reynum(double t,        /* absolute temperature(K)          */
            double g,        /* mass flux(kg/(m**2*s))           */
            double d,        /* hydraulic diameter(m)            */
            double *pt_mu,   /* dynamic viscosity (kg/(m*s))     */
            double *pt_kgas, /* gas thermal conductivity (W/(m*m*K))*/
            double *pt_re)   /* Reynolds number (fabs(g)*d/mu)    */

{
  double mu,re,kgas; /* see above pointers for definition */

  mu = mu0 * (t0 + t_suth)/(t + t_suth)*pow((t/t0),1.5);
  kgas = cp*mu/prandtl;
  re = fabs(g)*d/mu;
  if(re < 1.0)
     re = 1.0;
  *pt_mu = mu;
  *pt_kgas = kgas;
  *pt_re = re;
}

/******************************************************************
* FUNCTION: pipfr -Evaluate heat transfer and friction factor in  *
*                  smooth pipes                                   *
* FILENAME reynum.c                                               *
* PROGRAMMER I.Urieli    (FORTRAN)                                *
*            E. Malroy   (C Translation)                          *
* DATE:      12/01/94  (FORTRAN), 06/15/96 (C Translation)        *
* LAST MODIFICATION:  08/22/96   Eric Malroy                      *
* INCLUDE:  <stdio.h>,<math.h>,"define.h"                         *
* GLOBAL VARIABLES:                                               *
*   cp     - specific heat at const pressure (J/kg.K)             *
*   prandt - Prandtl number (0.71)                                *
* PROTOTYPES:                                                     *
*    void pipfr(double, double, double, double *, double *)       *
* PRE:   cp, prandt                                               *
* POST:  *ptr_ht, *ptr_fr                                         *
******************************************************************/
void pipfr(double d,      /* hydraulic diameter(m)               */
           double mu,     /* dynamic viscosity (kg/(m*s))        */
           double re,     /* Reynolds number (ABS(g)*D/mu)       */
           double *pt_ht, /* heat transfer coefficient (W/(m**2*K)) */
           double *pt_fr) /* Reynolds friction factor (Ff*Re)
                             (Ff: Fanning friction factor)       */

{
 double ht,fr;   /* see ptr definitions */

  if(re < 2000.0)
      fr = 16.0;
  else if((re > 2000.0)&&(re < 4000.0))
      fr = 7.3439e-4*pow(re,1.3142);
  else if(re >= 4000.0)
      fr = 0.0791*pow(re,0.75);
  ht = fr*mu*cp/(2.0*d*prandtl);
  *pt_fr=fr;
  *pt_ht=ht;
}

/******************************************************************
* FUNCTION:  foilfr - Evaluates the heat transfer & friction      *
*                     factor in a foil regenerator                *
* FILENAME reynum.c                                               *
* PROGRAMMER  E. Malroy                                           *
* Date:       08/13/96                                            *
* LAST MODIFICATION:  08/22/96                                    *
* INCLUDE:    <math.h>, "define.h"                                *
* GLOBAL VARIABLES:                                               *
*   cp      - specific heat at constant pressure (J/kg.K)         *
*   prandt  - Prandtl number (0.71)                               *
* PROTOTYPES:                                                     *
*    void foilfr(double,double,double,double *,double *,double *) *
* PRE: prandtl, cp                                                *
* POST: *pt_fr, *pt_st, *pt_ht                                    *
*******************************************************************/
void foilfr(double d,   /* hydraulic diameter (m)                 */
            double mu,  /* dynamic viscosity (kg/(m*s))           */
            double re,  /* reynolds number for foil               */
            double *pt_st, /* Stanton number                      */
            double *pt_ht, /* heat transfer coefficient (W/(m^2*k)) */
            double *pt_fr) /* Reynolds friction factor (Ff*Re)    */
                           /* (Ff: Fanning friction factor)       */
{
  double ht, fr, st;  /* see ptr definitions */

   if(re < 2000.0)
      fr = 24.0;
   else
      fr = 0.0791*pow(re,0.75);
   st = fr/(2.0*re*prandtl);
   ht = st*re*cp*mu/d;
   *pt_fr = fr;
   *pt_st = st;
   *pt_ht = ht;
}

/******************************************************************
* FUNCTION: matfr -Evaluate heat transfer and transport           *
*     properties in matrix                                        *
* FILENAME reynum.c                                               *
* PROGRAMMER I.Urieli    (FORTRAN)                                *
*            E. Malroy   (C Translation)                          *
* DATE:      12/01/94  (FORTRAN), 06/15/96 (C Translation)        *
* LAST MODIFICATION: 08/22/96                                     *
* INCLUDE:  <stdio.h>,<math.h>,"define.h"                         *
* GLOBAL VARIABLES:                                               *
*    prandt - Prandtl number (0.71)                               *
* PROTOTYPES:                                                     *
*    void matfr(double, double *, double *)                       *
* PRE:   prandt                                                   *
* POST:  *pt_st, *pt_fr                                           *
******************************************************************/
 void matfr(double re,     /* Reynolds number (ABS(g)*D/mu)      */
            double *pt_st, /* Stanton number (ht/(ABS(g)*Cp))    */
            double *pt_fr) /* Fr: Reynolds friction factor
                           (Ff*Re) (Ff: Fanning friction factor) */
{
 double st,fr;   /*  See the pointers above for the definition   */

   st = 0.46*pow(re,(-0.4))/prandtl;
   fr = 54.0 + 1.43*pow(re,0.78);
   *pt_st=st;
   *pt_fr=fr;
}