Hello! Can you give me advice, about arc-modeling in CFX!

I want, first of all, use simplest one-zonal model, with considering ( at first) only joule heating:

diagramm here: http://img300.imageshack.us/my.php?image=pical3.png

Algorithm is: 1)Computing temperature field by given temperature distribution on electrode surface. 2)Computing source energy terms in each arc point, by User Fortran procedures 3)Next iteration

The biggest problem it's step 2)! Which functions of USer Fortran or CEL should I use for calculating  E(z)=i(t)/[2π∫σ(r,z,t)rdr], where σ(T)=σTT(x,y,z,t)n, T - temperature ?

Thanks!!!

For step 2) I need use CFX USER_GETVAR function? Where I can find examples of using this function?

I think, I should use some of Data Acquisition Routines For exmaple USER_GETVAR function...

But, my algorithm used integration... I need integrate temperature by specific location ( by arc section areas ) ... And this location depend from mesh density and there not defined as <LOCATION> in CFX ( and have not CFX locator, and I can't use AreaInt functions )... Can you tell me, how realize the most simple integration in User Fortran!

Thanks CFXers!