How to analyse 'Joule Heat Energy'

[senthiappan]

Dear all,

I am working with ANSYS thermo-electric coupled field analysis. I am interested to find the Joule Heat Energy produced during a machining process, while giving current input. I am getting some wrong results. Can anybody tell my how to do this type of analysis? Thanks in advance.

-Karthi

"The ultimate measure of man is not where he stands in times of comfort, but where he stands at the moment of challenge and controvercy"
-Martin Luther King Jr.

 

[harry123456]

I have done some coupled field thermoelectic analysis with applied voltage instead of current. If you describe your problem I could try and help you if I can
harry

 

[senthiappan]

hi harry.. thx for your response. I am interested to find the Joule heat produced on the workpiece during a spark erosion process in an Electric Discharge Machine. The workpiece and electrode is submerged in a dielectric medium. I am giving about 200A current input for a short pulse time. For every pulse a micro crator is created on the workpiece, due to the melting of metal and followed by a splashing of dielectric medium surround it. Here my task is to confirm the temperature and the Joule heat energy produced during the pulse time.

My question is how to do this in ANSYS? Is it enough to conduct a transient thermal analysis for this, rather than a thermoelectric analysis?

"The ultimate measure of man is not where he stands in times of comfort, but where he stands at the moment of challenge and controvercy"
-Martin Luther King Jr.

 

[harry123456]

The problem is involved. If you are interested in the joule heat and want to simulate as closeley then thermoelectric analysis would be appropriate. In this you can either apply voltage or current at the nodes which will result in heating. I think you might also need to consider element birth and death which I think is used in melting but I am not sure.
Harry

 

[senthiappan]

hi harry...as u said, the element birth and death option is my next phase to find the geometry of the crator formed by the erosion. prior to that, i would like to find the temperature and Joule profile in the work piece. could u tell me the step-by-step procedure to run the thermoelectric analysis? because i do have problem there. i would like to know the material models those should be added and the way of execution.

"The ultimate measure of man is not where he stands in times of comfort, but where he stands at the moment of challenge and controvercy"
-Martin Luther King Jr.

 

[harry123456]

ANSYS has a coupld of examples. But basically after you model your workpiece and electrode you will either apply voltage at the electrode areas or current at some nodes. You will mainly need the thermal conductivity and electrical resistivity of the two materials. This might be a function of temp but initially just assume constant. Again I dont know exactly the process but I think the electrode and workpiece need to be in contact in some way (maybe areas glued to each other) so the heat will be transmitted. Basically, your BCs are voltage/current and some initial temperature will be needded to be specified (room temp?).
harry