[Mingli163]

Hi friends, hope you are all well!
I have encountered a problem with how to call the current density and electric potential from Fluent in UDF.
I'm using Fluent to simulate the sheath on the arc roots. The sheath is a thin layer, and its electrical conductivity is calculated from current density and electric potential by Ohm's law.
Now I plan to use DEFINE_PROPERTY(electric_conductivity, c,t) to define the electrical conductivity. However, I don't know how to call the current density and electric potential from Fluent in UDF. I know Fluent provides some macro like C_T(c,t) to call the temperature, but I can't find the macro to call the properties I want.
Could anyone give me some advice to solve this problem?
Thanks!

[shanma29]

hi, we can call the potential using the macro C_PHI_1(c,t), but I didn't know how to call current density, joule heating effect value or electrical conductivity. Can you share me the macro name if you have found the answer. Thank you

[rodrigovime]

I did a similar calculation but for an arc in LTE, and I found that it's much faster create a UDS for the electric potential and magnetic field to have access to all the variables you need and including the electrical conductivity as a temperature dependent function

[Thore850]

Current Density is equal to the multiplication of the gradient of the potential with the electrical conductivity, which means you should be able to calculate your current density as:

DEFINE_EXECUTE_AT_END(Current_Density) {

face_t f;
cell_t c;
Thread* t;
Domain* d = Get_Domain(1);

thread_loop_c(t, d)
{
begin_c_loop(c, t)
{

/* Electrons */

C_UDMI(c, t, 0 ) = C_ELEC_COND(c,t) * C_PHI_1_G(c,t);

/* A/m^2 = A/(V*m) * V/m */

}end_c_loop(c, t)
}

}

Normally i use UDS to calculate my potential equations, therefore i havent tried this code, so let me know if it works!

Best regards

Thore

[shanma29]

Thank you