Learning Forum

[pavankonchada123]

I am trying to use below udf for surfacearea_volume in ansys fluent for porous media in reactions but Iam not able to see any udf in drop down

DEFINE_PROFILE(Surface_area_Volume_ratio,t,i)
{
#if !RP_HOST  
 cell_t c;
  real x[ND_ND];
  real void_fraction,solid_volume;
  begin_c_loop(c,t)
    {
        if(C_DPMS_CONCENTRATION(c,t)>0)
        {
        solid_volume = C_DPMS_CONCENTRATION(c,t)/2300;
      void_fraction = (1-solid_volume)/solid_volume;
      F_PROFILE(c,t,i) = M_PI*pow((6*C_VOLUME(c,t)*void_fraction/M_PI),0.66666)/C_VOLUME(c,t);
        }
      else
         F_PROFILE(c,t,i) =0;  
        }
    
  end_c_loop(c,t)
   #endif    
}

[pavankonchada123]

And also tried to use expression but it is saying expression is not single valued

void_fraction1 :

(1 - (DPMConcentration*1[m^3/kg] / 2300)) / (DPMConcentration*1[m^3/kg] / 2300)

surface_volume:

3.14*1[m^-1] / (CellVolume*1[m^-3]) * (6 * CellVolume*1[m^-3]*void_fraction1 / 3.14) ^ 0.666

[DrAmine]

What do you want to modifiy? Probably it requires a single valued expression and not a field.

[pavankonchada123]

Surface to volume ratio for reaction in porous media.

Can you let me know which macro should I use define profile is not working

[DrAmine]

That input cannot be provided via a profile it requires a single valued input. 

[pavankonchada123]

But my value depends on void fraction on each cell of domain. Is there any way I can define different values on different cells with voidfraction as variable

[DrAmine]

 

Built-in capability: I need to say no. You require more efforts to do that. For that reason, I think we should enhance this and allows the value to be a field input. I will discuss this with my colleagues.