Some problems about UDF in fluent5.4
 

Hi,Fluent Users: 1> I have a problem about my compiled UDF in fluent5.4.

In fluent UDF mannul,it is said "Copy Makefile.udf from the directory shown above to your library directory (e.g., libudf), and name it makefile",and "Copy makefile.udf from the directory shown above to your /src directory, and name it makefile".

But in my path/Fluent.Inc/fluent5.4 /src/,I have just makefile_nt.udf and user_nt.udf.So I consider makefile_nt.udf as Makefile.udf and user_nt.udf as makefile.udf.So I copy makefile_nt.udf to my library directory (e.g.,libudf), and name it Makefile,and copy user_nt.udf to my /src directory,and name it user_nt.

When I Compile or Link my Compiled UDF, I also type the complete path to the library directory. But I get the following error: Opening library "f:\guochuhybrid\wangyou\libudf\ntx86\2d\libudf.dl l"... Error: open_udf_library: couldn't open library: f:\guochuhybrid\wangyou\libudf\ntx86\2d\libudf.dll Error Object: ()

2> I have another problem,Do I need to set up 2D or 3D directories in my ultra?

3> The last problem is about the unit of pre-exponential factor in Arrhenius expression.

k=A*exp(-E/RT)

The unit of the forward rate constant for reaction k is m^3/(kmol-S).The unit of activation energy for reaction is J/kmol.The unit of universal gas constant is J/(kmol-K).Then E/RT is dimensionless.So the unit of pre-exponential factor(A) is m^3/(kmol-S).

But in fluent reactions pannel, pre-exponential factor(A) is dimensionless.And in literatures,the unit of pre-exponential factor(A) is 1/S.

Would you give me some advice about these?Any ansewer will be welcome.

Thank you.

Mark 2001.8.12

Re: Some problems about UDF in fluent5.4
 

Check for the documentation on compiling udfs on NT. This process is different from on unix as outlined in the udf manual.

This is not so straightforward. It depends on the power that the concentration is raised to. In essence the total rate is

R = k * C^n

where C = kmol/m3

k = 1/(s-(kmol/m3)^(n-1))

R = kmol/m3-s

Greg

Re: Some problems about UDF in fluent5.4
 

Hi,

Thank you for your reply.

I just have documentation on compiling udfs on UNIX Would you like to send me some copy about compiling udfs on NT?

Thank you.