Should that not fall out of the physics? I.e. you have some electric current physics, which I assume is what is heating up things, so you would probably need a coupling expression stating the heating as a function of current?

Dear René Christensen :

" Should that not fall out of the physics? I.e. you have some electric current physics, which I assume is what is heating up things, you are right so you would probably need a coupling expression stating the heating as a function of current? "

A "coupling expression ? Okay , What coupling expression? and where I need to write it ?

Thank you for your help René,

Regards !

Hi Franklin,

I do not understand why you want a linear source... I assume that what you want is to couple the electrical losses to your heat transfer right? For that, you need to select a general Heat source, and one of the options will be the coupling from the multiphysics. Otherwise, you can couple it manually, for that you need to add the electrical losses, which from the top of my head will be ec.Qe (check by clicking in the field ctrl+space, you will see all the options computed from models).

Kind regards,

Julian

Dear J. Anaya :

Thank you very much for your answer,

I think you are right. Since what I want/need is to get the Heat Source from the "Electric Currents" physics, since it is a coupled problem I need to use the "General Heat Source".

But the problem is that when I try to stablished the Heat Source like this, using the option of "Volumetric loss density, electromagnetic (ec)" (this is bringing the solution automatically from the Electric Currents, as you suggest).

I don't get any Temperature, this is what I get: (see pls the attached image)

So, It makes sense this is the way I need to do it, but I don't know what I'm doing wrong

Thanks for the Help Julien

Are you sure you do not have any temperature gradient? It is not a problem of the magnitudes involved? I have the feeling that you may have a very very small power density from the electric currents...

Dear J. Anaya :

I see, well it is a MV Cable, (1.54 in total diameter) subjected to a voltage difference of 35 000 V

Let me, later when I arrive back home, check again the parameters and magnitudes of the problems.

And if you don't mind, let me come back to you afterwards.

Thank you friend

Regards !

Dear J. Anaya :

I checked the Graph for the solution of the Temperature, and imput parameters of the problem, but I still don't know what the problem is.

This is the Graph for the Temperature (image attached)

I did solve it with the "General Source" obtained from the "electric currents (ec)" Physics

You cna see in the image, on the color bar to the right, that there is no Difference in T. Everything is at 303.

I did see the imput parameters of the problem one more time, but there aren't many.

Is just the imput Voltage, the Dimensions of the conductor, and I selected the material from the Material Library (Copper)

Maybe I'm doing some mistake on the BC inside the "electric current (ec)" Physics ?

I don't know if you would mind to give it a look to the model, if I send it to you, I'm using ver.5.6.

You will help me a lot,

Best Regards !

Dear J. Anaya :

I hope don't bother, Can you help me further ?

Regards !

I can try Franklin, but I cannot open your models... I cannot use my license for that.

I see you are using 2 different studies there, electrostatics and electric currents, also you have multiphysics. What are you coupling to thermal? Also, the Multiphysics does account for the Thermal-Electric coupling, you do not need to add the extra heat source in the thermal, that is done only if you remove the Multiphysics to create a one-way coupling. Something I do not understand well is how you are setting the current, I assume it should be an out of plane current right? But you have a terminal there, that is a bit strange... I would set the boundary to a Normal current density boundary condition, being the current density the current divided by the crosssection of the cable... Otherwise, you do not really have a current flowing in the wires. The terminal boundary condition is an entrance point to the model but in a 2D model like this one, I'm not sure if it will work (although it is defined as the vector integral of a current density on the surface it is applied).

Kind regards,

Julian

Dear Anaya :

I see, and thank you for your further Help. I will address your questions between your lines

"

I see you are using 2 different studies there, electrostatics and electric currents, also you have multiphysics Yes, when I selected the "Joule Heating" Physics to add it to my model this one went into the model with the Multiphysics: "Electromagnetic Heating (emh1)". What are you coupling to thermal? What I'm coupling to the Thermal physics is the "electric currents (ecs)" Also, the Multiphysics does account for the Thermal-Electric coupling, you do not need to add the extra heat source in the thermal, that is done only if you remove the Multiphysics to create a one-way coupling I see !, So I don't need to add an extra Domain Condition ("Heat Source") to the model. Something I do not understand well is how you are setting the current

I am not setting up a current, but an Imput Voltage value (35 kV). What I'm doing is: either on the "Electrostatics (es)" and "Electric Currents (ec)" physics, I added a Domain condition to each one; a "Terminal" Domain, to stablish the value of the Voltage at the domain that represents the central copper conductor (my model is a 2D model). My logic was this one because on my real scenario I have a 10 meters burried line underground, and this power line is subjected to a difference in voltage of 35 000 kV. So I'm trying to represent the Joule Effect this condition of a 35kV drop will caouse on the central conductor. but this is a condition in the 3D scenario, considering the lengtt dimension and the two electrodes/terminals.

, I assume it should be an out of plane current right? Yes But you have a terminal there, that is a bit strange I'm sure the problem is there... I would set the boundary to a Normal current density boundary condition In both physics ? "Electrostatics (es)" and "Electric Currents (ec)", or just in one of the two ?, being the current density the current divided by the crosssection of the cable but I don't know the Current, the nominal imput data of the problem is the Voltage... Otherwise, you do not really have a current flowing in the wires I understand, so if my Imput information is the voltage of the line, rather than the current, how I can make it work using a "Normal Current Density BC" as you suggested ?.

The terminal boundary condition is an entrance point to the model but in a 2D model like this one, I'm not sure if it will work (although it is defined as the vector integral of a current density on the surface it is applied). I understand, there is a way to know the Normal Current Density from the Voltage Drop (25kV in my case) of the line ?

"

Dear Julien thank yo for you help, I wil keep trying

Regards !

well the first approach may be to get a quick number for the current based on Ohm's law (from the impedance of the line). Main problem I see here is that you cannot really apply a voltage port in a 2D simulation like this one. If you set the voltage for that boundary the only thing you have is a fix point for the voltage, but that will not make any charge to move out of plane...