Problem accessing material properties in UDF for Multiphase Multispecies
 

Hi,

I am simulating a fuel cell and have written a series of UDFs which work for a single phase gas-mixture. Now I am trying to simulate multiphase with an additional liquid water phase and I have a problem with accessing the material properties in order to populate a series of integers that I use later in other UDFs. The UDF is an EXECUTE_ON_LOADING so I am not passed any threads to start with and I'm sure it's a problem with getting the right thread for the gas_mixture phase. Please could anyone suggest how to correctly work through the domain and thread structure.
Thanks in advance
Tom
Here is the UDF:

/* Species Variables */
int i_H2 = 99;
int i_O2 = 99;
int i_H2O = 99;
int i_N2 = 99;
char hydrogen[2] = "h2";
char water[3] = "h2o";
char oxygen[2] = "o2";
char nitrogen[2] = "n2";

DEFINE_EXECUTE_ON_LOADING(record_species, libname)
{
int i;
char *spe_name;
Domain *d=NULL;
Material *mix_mat=NULL, *sp;
d=Get_Domain(1);
mix_mat= mixture_material(d);
mixture_species_loop(mix_mat,sp,i)
{
spe_name=MIXTURE_SPECIE_NAME(mix_mat,i);
if(strcmp(spe_name,hydrogen)==0)
i_H2 = i;
else
if(strcmp(spe_name,oxygen)==0)
i_O2 = i;
else
if(strcmp(spe_name,water)==0)
i_H2O = i;
else
if(strcmp(spe_name,nitrogen)==0)
i_N2 = i;
else
Message("Unidentified Species in List, %s\n",spe_name);

}
Message("H2: %d O2: %d H2O: %d N2: %d\n",i_H2,i_O2,i_H2O,i_N2);
}

Sorry I forgot to include a section of code at the top of the UDF in case anyone thinks that may be the problem

#include "udf.h"
#include <stdio.h>
#include <conio.h>
#include <stdlib.h>
#include "materials.h"
#include "string.h"

Thanks

I have now figured it out. the UDF manual had the answer after all - although it was quite difficult to find (excuses excuses)...

The correct code is below if anyone reading back finds this post

DEFINE_EXECUTE_ON_LOADING(record_species, libname)
{
int i;
int phase_domain_index = 0;
char *spe_name;
Domain *d=NULL,*sub_d=NULL;
Material *mix_mat=NULL, *sp, *gas_phase;
if(NULL == (d=Get_Domain(1)))
Error("NULL pointer assignment on domain!\n");
if(NULL == (sub_d=DOMAIN_SUB_DOMAIN(d,phase_domain_index)))
Error("NULL pointer assignment on subdomain!\n");
if(NULL == (mix_mat= mixture_material(sub_d)))
Error("NULL pointer assignment on mixture!\n");
//mix_mat= mixture_material(d);
mixture_species_loop(mix_mat,sp,i)
{
spe_name=MIXTURE_SPECIE_NAME(mix_mat,i);
if(strcmp(spe_name,hydrogen)==0)
i_H2 = i;
else
if(strcmp(spe_name,oxygen)==0)
i_O2 = i;
else
if(strcmp(spe_name,water)==0)
i_H2O = i;
else
if(strcmp(spe_name,nitrogen)==0)
i_N2 = i;
else
Message("Unidentified Species in List, %s\n",spe_name);

}
Message("H2: %d O2: %d H2O: %d N2: %d\n",i_H2,i_O2,i_H2O,i_N2);
}

i was working this problem recently. When using the Mixture_species_loop macros, it required the material thread point to a mixture material, if the thread point to a pure species, i will not work and the fluent wil goes error.
anyway thanks for you anwser.@pmtgt