[malcolmcheong]

Hello everybody!

Recently I am trying to modified the reaction rates when using the EDC model in fluent. The UDF manual of fluent shows that I can implement that by using DEFINE_NET_REACTION_RATE. And here is the example provided in the UDF manual :

#include "udf.h"

DEFINE_NET_REACTION_RATE(user_net_reaction_rate, p, temp, yi, rr, jac)
{
int i;
for(i=0;i<n_spe;i++)
rr[i] = 1./(real)n_spe - yi[i];
}

However, in my own scheme I need to call the viscosity of the current cell and I will use the macro C_MU_L(c, t), which means I need to know the information of the current cell and thread. But this reaction rate function does not providing the information. How can I solve this problem? or how can I acquire the cell and thread information when I use DEFINE_NET_REACTION_RATE?

Any suggestions will be appreciated. Thank you.

[pakk]

In my version of Fluent (v15), the macro is different:

DEFINE_NET_REACTION_RATE(net_rxn,c,t,particle,pressure,temp,yi,rr,jac)

So the reaction rate function does give the information. Which version are you using?

[malcolmcheong]

Thank you for your reply. I am using Fluent 6.3 and I have tried the new function format with cell and thread information.

Actually I am trying to implement the default EDC model using my own UDF and here is the code:

#include "udf.h"

DEFINE_NET_REACTION_RATE(default_edc, c, t, particle, pressure, temp, yi, rr, jac)
{

int i = 0;

double ctau, cxi, tau, xi;

//DEFINE ctau and cxi
ctau = 0.4082;
cxi = 2.1377;

xi = cxi*pow(C_MU_L(c,t)*C_D(c,t)/(C_R(c,t)*C_K(c,t)*C_K(c,t)),0.25);
tau = ctau*sqrt(C_MU_L(c,t)/(C_D(c,t)*C_R(c,t)));

for(i=0;i<n_spe;i++)
{
rr[i] = C_R(c,t)*xi*xi/(ctau*(1. - xi*xi*xi))*(C_YI_EDC(c,t,i) - yi[i]);
}
}

Unfortunately the code did not work. When I hook it and run the simulation primitive error occurred. Then I realize that the c and t this function passes may be different from what I need in the macros such as C_D(c, t). The c and t this function passes is for the particles, right?

[loop]

Hello malcolmcheong,

Did you manage to solve the problem with using the DEFINE_NET_REACTION_RATE. I am trying to use it as well and am facing similar problems. Would appreciate any suggestions...

[Aslan_nzr]

Hello everybody

Did anyone succeed in rewriting the EDC default model by udf?!!