FLUENT填充床反应器模拟

#include "udf.h"

real delta_t;

int time_step;

#define d_b 0.00683        /* mean diameter of bulk material */

real rho_b = 2250.;        /* particle density */

real cp_b  = 835.;         /* specific heat capacity */

real A_V_sphere = 6.0/d_b;  /* area-to-volume ratio of a sphere*/

real A_b_V;                 /* area-to-volume ratio */

enum

{

  T_B,

  N_REQUIRED_UDS

};

DEFINE_ADJUST(pm_adjust, domain)

{

  delta_t = RP_Get_Real("physical-time-step");

  time_step = RP_Get_Integer("time-step");

}

DEFINE_UDS_UNSTEADY(pm_first_order, c, t, i, apu, su)

{

  real vol;    /* cell volume */

  real vol_m1; /* cell volume time step minus 1 */

  real fac;    /* factor in time derivative */

  real fac_m1; /* factor at time step minus 1 */

  real eps_b = 1.0 - C_POR(c,t);  /*solid volume fraction*/

  vol    = C_VOLUME(c,t);

  vol_m1 = vol;

  fac    = rho_b*cp_b*eps_b;

  fac_m1 = fac;

  *apu    = -fac*vol / delta_t;

  *su     = fac_m1*vol_m1*C_UDSI_M1(c,t,i)/delta_t;

}

DEFINE_UDS_UNSTEADY(pm_scnd_order, c, t, i, apu, su)

{

  real vol;    /* cell volume */

  real vol_m1; /* cell volume time step minus 1 */

  real vol_m2; /* cell volume time step minus 2 */

  real fac;    /* factor in time derivative */

  real fac_m1; /* factor at time step minus 1 */

  real fac_m2; /* factor at time step minus 2 */

  real eps_b = 1.0 - C_POR(c,t);

  if ((time_step < 2) || (n_time_levels == 2))

    pm_first_order(c,t,i,apu,su);

  else {

    vol    = C_VOLUME(c,t);

    vol_m1 = vol;

    vol_m2 = vol;

    fac    = rho_b*cp_b*eps_b;

    fac_m1 = fac;

    fac_m2 = fac;

    *apu    = - 1.5*fac*vol / delta_t;

    *su     =  (2*fac_m1*vol_m1*C_UDSI_M1(c,t,i) -

                0.5*fac_m2*vol_m2*C_UDSI_M2(c,t,i))/delta_t;

  }

}

real htc(cell_t c, Thread *t)

{

  real Nu, Re, Pr;

  Re = ND_MAG(C_U(c,t),C_V(c,t),C_W(c,t))*d_b*C_R(c,t)/C_MU_L(c,t);

  Pr = C_CP(c,t)*C_MU_L(c,t)/C_K_L(c,t);

  Nu = 2.  1.1 * pow(Re,0.6) * pow(Pr,1./3.);

  return Nu*C_K_L(c,t)/d_b;

}

DEFINE_SOURCE(energy_source, c, t, dS, eqn)

{

  real pref;

  real source;

  real eps_b = 1.0 - C_POR(c,t);

  A_b_V = eps_b*A_V_sphere;

  pref = htc(c,t)*A_b_V;

  source = -pref*(C_T(c, t) - C_UDSI(c, t, T_B));

  dS[eqn] = -pref;

  return source;

}

DEFINE_SOURCE(uds_source, c, t, dS, eqn)

{

  real pref;

  real source;

  real eps_b = 1.0 - C_POR(c,t);

  A_b_V = eps_b*A_V_sphere;

  pref = htc(c,t)*A_b_V;

  source = pref*(C_T(c, t) - C_UDSI(c, t, T_B));

  dS[eqn] = -pref;

  return source;

}