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#1 |
New Member
Join Date: Jul 2024
Posts: 2
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Hello,
I want to calculate gas mass transfer coefficient kla by using the following UDF: #include "udf.h" /* Define constants */ #define D 2.5e-9 /* mass diffusivity (m^2/s) */ #define rho_l 1000.0 /* density of liquid (kg/m^3) */ #define mu_l 0.001 /* viscosity of liquid (Pa.s) */ #define alpha_air_phase 3 #define water_phase 2 /* Define UDF to calculate oxygen mass transfer coefficient kla */ DEFINE_ON_DEMAND(calc_kla) { Domain *domain = Get_Domain(1); Thread *cthread; cell_t c; /* Loop over all cells in the domain */ thread_loop_c(cthread, domain) { if (FLUID_THREAD_P(cthread)) /* Check if the thread is a fluid thread */ { Thread **pt = THREAD_SUB_THREADS(cthread); Thread *primary_phase_thread = pt[water_phase - 1]; /* Water */ Thread *secondary_phase_thread = pt[alpha_air_phase - 1]; /* Air */ /* Loop over all cells in the fluid thread */ begin_c_loop_all(c, cthread) { real alpha_air = C_VOF(c, secondary_phase_thread); /* Volume fraction of air */ real epsilon = C_D(c, cthread); /* Turbulence dissipation rate */ real d_b = C_PHASE_DIAMETER(c, secondary_phase_thread); /* Bubble diameter */ /* Calculate k_L using the Lamont and Scott model */ real kl = 0.4 * pow(D, 0.25) * pow(epsilon, 0.25) * pow(rho_l / mu_l, 0.25); /* Calculate 'a' */ real a = 6.0 * alpha_air / d_b; /* Calculate kla */ real kla = kl * a; /* Store kla in a user-defined memory location */ C_UDMI(c, cthread, 0) = kla; } end_c_loop_all(c, cthread) } } } The UDF was successfully compiled and loaded. However, after I finished the calculation and went to contours > contours of user defined memory > user memory 0, the max and min boxes were grayed out. Also, when I tried to execute on demand, I received: Node 0: Process 19108 has received the signal SIGSEGV. The fluent (f1) process encountered an error: the connection was reset. How can I resolve this issue? Thanks in advance! |
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#2 |
New Member
Join Date: Jul 2024
Posts: 2
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This is the log file:
My ansys fluent shut down every time when I want to excecute a UDF on deman. This is the log file: Node 0 Fatal signal raised sig = Segmentation fault 6457e430 CX_Primitive_Error ae33b9d0 log2f 645f2fe0 logical_right_shift a83be530 _C_specific_handler b1054f20 _chkstk b0fcddd0 RtlFindCharInUnicodeString b1054010 KiUserExceptionDispatcher 8c690000 Ordinal0 61e8c170 fluent_fprintf 645dcf80 eval 61f44870 PRF_Command_Start 61f46fa0 PRF_Node_repl 61f52db0 Delay_Error 645f2fe0 logical_right_shift b0872560 BaseThreadInitThunk b100af00 RtlUserThreadStart Error [node 0] [time 7/4/24 21:15:2] Abnormal Exit! |
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Tags |
mass transfer coefficient, multiphase flows, udf |
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