CFD Online Discussion Forums - conductivity, viscosity, and density udf

Quote:

Originally Posted by mdakbari (Post 486023)

hello friends, i have 3 .c files that need to be checked cause i am not sure which they work or not.
i really appreciate u to check it for me,
i'm waiting for ur comments dudes
best wishes for u

Attachment 30141

Attachment 30142

Attachment 30143

Hi,
Can you explain what problem you are facing with the code? You don't have to have 3 different files for your code. You can place them all in one file (since they are not that lengthy).
Since I don't know what you are trying to do. I will suggest you try and debug the code using a simple way as follows.
1) Do the calculations in an Excel sheet with different inputs
2) Place some lines to print the output to the console in Fluent.
2a) Note that I have put a limit to the number of times your code will print to the console so that it does not hang up your system.
I hope that will help in what you are trying to do. I did not run the code but I think it looks OK, the red parts are my addition to your code to help you in debugging, I have not changed anything, you can remove them after the debugging.

Regards

APPENDIX
/************************************************** *******************
UDF that simulates solidification by specifying a temperaturedependent
thermal conductivity property
************************************************** ********************/
#include "udf.h"

int printStopper=0; /*This is a dummy counter */
DEFINE_PROPERTY(cell_density,cell,thread)
{
real rho;
real temp = C_T(cell,thread);
rho=(-3.570*(pow(10,-3))*(pow(temp,2))+(1.88*temp+753.2));

if(printStopper<=100)
{printStopper++;
CX_Message("*****Cell Temp: %3.2f Kelvin, Rho= %E kg/m3 \n",temp,rho);
}
return rho;
}
DEFINE_PROPERTY(cell_conductivity,cell,thread)
{
real ktc;
real temp = C_T(cell,thread);
ktc=(-8.354*0.000001*(pow(temp,2)))+((6.53*0.001*temp)-0.5981);

if(printStopper<=100)
{printStopper++;
CX_Message("*****Cell Temp: %3.2f Kelvin, KTC= %E W/m.K \n",temp,ktc);
}
return ktc;
}

DEFINE_PROPERTY(cell_viscosity,cell,thread)
{
real mu;
real temp = C_T(cell,thread);
mu=2.591*(pow(10,-5))*(pow(10,(238.3/(temp-143.2))));

if(printStopper<=100)
{printStopper++;
CX_Message("*****Cell Temp: %3.2f Kelvin, Viscosity= %E Pa.s \n",temp,mu);
}
return mu;
}