[srj007]

Dear all,
i am going to simulate tube in tube type simple metal hydride reactor tank in ANSYS FLUENT 15.I am using udf as follows, i got error as
"fatal signal (segmentation fault)''
i am using LaNi5 alloy, please help me for removing the error occurred.

#include"udf.h"

/* Input Boundary Conditions */
#define T_i 293.0 /* Inlet temp in K */
#define T_f 293.0 /* Coolant fluid temp in Kelvin [K] */
#define P_i 0.8e5 /* Inlet pressure in pascals */
#define h_o 2500 /* Heat transfer coeff in W/m^2-K */
#define x_i 0.0 /* Initial value of H/M for reaction to START */
#define x_f 1.0 /* Final value of H/M for reaction to STOP @ saturation */

/* Properties of Metal Alloy [LaNi5] */
#define rho_m 8200 /* Density in kg/m^3 */
#define Cp_m 419 /* Sp heat in J/kg-K */
#define K_m 1.2 /* Thermal conductivity in W/m-K */
#define por 0.5 /* Porosity */
#define NA 6 /* Number of atoms in Mischmetal alloy */
#define M_m 434 /* molecular weight of mischmetal alloy in g/mol */
#define rho_ss 8323 /* Density of MH @ saturation kg/m^3 */
#define rho_s 8200 /* Density of MH kg/m^3 */
#define E_a 21170 /* Activation energy in J/mol H2 */
#define per 1e-8 /* Permeability */
#define DELTA_S 108 /* Entropy of Formation J/mol H2-K */
#define DELTA_H 28000 /* Enthalpy of Formation J/mol H2 */
#define wt 0.015 /* Hydrogen weight Storage Capacity 1.5% of Mischmetal */

/* Properties of Hydrogen */
#define K_g 0.127 /* Thermal Conductivity in W/m-K */
#define Cp_g 14283 /* Sp heat in J/kg-K */
#define rho_g 0.0838 /* Density in kg/m^3 */
#define M_g 2.016 /* Molecular weight in g/mol */

/* CONSTANTS */
#define R_u 8.314 /* Universal gas Constant J/mol-K */
#define k_a 59.187 /* Reaction Constant for absorption in (sec)^-1 */

/* Initialization of cell property of scalar i.e. 'x' */
DEFINE_INIT(my_init_fuc,d)
{
cell_t c;
Thread *t;
thread_loop_c(t,d)
{
begin_c_loop_all(c,t)
{
C_UDSI(c,t,0)= 0;

}
end_c_loop_all(c,t)
}
}

/* Energy Equation HEAT SOURCE term */
DEFINE_SOURCE(heat_generation,c,t,dS,eqn)
{
real c_a;
real q_a;
real physical_dt;

physical_dt = RP_Get_Real("physical-time-step");
c_a= (rho_ss-rho_s)*(1-por)*(C_UDSI(c,t,0)-C_UDSI_M1(c,t,0))/physical_dt;
q_a= ((1000*c_a*(DELTA_H/M_g)));
dS[eqn]=0;
C_UDMI(c,t,0)=q_a; /* Memory allocation for storing 'heat generation' */
return q_a;

}

/* UDS for solving Kinetic equation i.e. dx/dt eqn */
DEFINE_UDS_UNSTEADY(uds_time,c,t,i,apu,su)
{
real physical_dt;
real vol;
real rho;
real phi_old;
physical_dt = RP_Get_Real("physical-time-step");
vol = C_VOLUME(c,t);
rho = 1; /* for varying density use rho = C_R_M1(c,t); */
*apu = -rho*vol/physical_dt;
phi_old = C_STORAGE_R(c,t,SV_UDSI_M1(0));
*su = rho*vol*phi_old/physical_dt;
}

/* Kinetic Equation SOURCE term */
/* Convection & Diffusion part are zero */
DEFINE_SOURCE(uds_source,c,t,dS,eqn)
{
real tp;
real rate;
real P_eq;
real cond;
real x_now;

tp = C_T(c,t);
P_eq = pow(2.718,((DELTA_S/R_u)-(DELTA_H/(R_u*tp))))*pow(10,5);
cond = P_i/P_eq;

if(cond>1)
{
rate = k_a*pow(2.72,(-E_a/(R_u*tp)))*((P_i/P_eq)-1)*((C_UDSI(c,t,0) - x_f)/(x_i - x_f));
dS[eqn] = k_a*pow(2.72,(-E_a/(R_u*tp)))*((P_i/P_eq)-1)*(1/(x_i - x_f)); /* Derivative of SOURCE w.r.t. DEPENDENT variable */
}
else
{
rate = 0;
dS[eqn] = 0;
}

C_UDMI(c,t,2) = rate;
return rate;

}