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Building expressions on CFX

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Old   January 18, 2016, 04:55
Default Building expressions on CFX
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FrC
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Francesco
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Hi guys,

this is my first post on CFD online!

I would to have an information on building expressions on CFX starting on this UDF:


#include "udf.h"

#define OMEGA 7.26E-3
#define K_F0 0.0257
#define K_S0 1.0
real
k_solid(real e_gas)
{
real k_sol;
real a = K_S0/K_F0;
real b = 1.25*pow((1.-e_gas)/e_gas, 10./9.);
real t1 = (a-1.)/pow((1.-b/a),2.0)*(b/a)*log(a/b);
real t2 = -((b-1.)/(1.-b/a))-0.5*(b+1.);
real gm = (2./(1.-b/a))*(t1+t2);
real k_bs = K_F0*(OMEGA*a + (1.-OMEGA)*gm);
k_sol = k_bs/sqrt(1.-e_gas);
return (k_sol);
}
DEFINE_PROPERTY(conduct_gas,cell,thread)
{
real k_bf, k_gas;
k_bf = K_F0*(1.-sqrt(1.-C_VOF(cell,thread)));
k_gas = k_bf/C_VOF(cell, thread);
return (k_gas);
}

DEFINE_PROPERTY(conduct_solid,cell,thread)
{
real k_sol;
real epsi_max = 1.-10*SD_EPS;
real epsi = MIN( epsi_max, (1.-C_VOF(cell,thread)));
k_sol = k_solid(epsi);
return (k_sol);
}

In order to transcribe this program in CFX is necessary to know the meaning of a few variables like C_VOF, e_gas, SD_EPS.
I tried searching in the Ansys library but I didn't find nothing.
Where I can found them?....or does someone know the variables associated with them?

Thanks for the support.
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Old   January 18, 2016, 08:49
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Opaque will become famous soon enough
If you provide the names of those variables in FLUENT, I am sure someone can pitch in for the equivalent names in CFX.

By not doing so, only those familiar with FLUENT UDF variables and ANSYS CFX Expressions would be able to help you.

summary: the more information you can provide, the better.

Hope the above helps
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Old   April 3, 2019, 06:55
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Akash
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Dear Sir/Madam,

I am working on a fluidized bed simulation and use the same code to specify the thermal conductivity. From what I concluded, e_gas is the voidage, C_VOF the volume fraction, however I couldn't find anything on SD_EPS, do you know what that stands for?

Thank You,

Sincerely,

Akash ajodhia
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cfx expressions, c_vof, e_gas, sd_eps


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