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August 28, 2017, 03:28 |
metal hydride reactor simulation
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New Member
suraj godase
Join Date: Jul 2017
Location: Maharashtra, India
Posts: 4
Rep Power: 9 |
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; } |
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