## General Mechanical

Topics relate to Mechanical Enterprise, Motion, Additive Print and more

#### Heat Generation

• chris1992
Subscriber

Hello!

I want to simulate a simple body which is producing its own heat. The produced heat depends on the temperature of the body and should be considered as different functions (3 functions) or as a table (produced heat over temperature). I have no experience with ANSYS and I also read many manuals but I didn't find anything useful for me. Could somebody please help me? Thanks in advance.

Best regards.

Christopher

• peteroznewman
Subscriber

Hello Christopher,

I'm interested in helping. Please make a sketch of the shape of the body and post an image in your reply. You also have to define the thermal conductivity of the material.

For each surface of the body, you have to say what happens to heat at that surface. The choices are: insulated, fixed temperature, convective heat transfer, or fixed heat flow (leaving out Radiation from this list for simplicity).

Best regards,

Peter

• chris1992
Subscriber

Hello Peter,

The shape of the body is a simple rectangle with very thin thickness and looks like this:

Size of the elements are all the same. Thermal conductivity in plane is 20W/mK, perpendicular to it its nearly 1 W/mK.

Actually I'm working with an other program and I only want to know if the implementation of a Heat Generation is possible in the way I thought.

Therefore every element of this body should produce its own Heat. The Heat Generation should be described by different functions or by a table

depending on the elements temperature.

Best regards,

Christopher

• peteroznewman
Subscriber

Hello Christopher,

Here is a simple model and you can see that Function is one of the choices for Internal Heat Generation,
while Tabular is only as a function of time.

And while TEMP is the variable name of nodal output temperatures for results, it apparently doesn't like it in this formula.

I'm going to need some help here from experts in the community.  Let's see what others can contribute.

Regards,

Peter

Attached is an ANSYS 18.2 archive.

• chris1992
Subscriber

Hello Peter,

thank you very much. That's exactly the information I was searching for. Maybe there has to bei added some information at the "TEMP"-part for the function. In LS-DYNA there has to be written TEMP(293) for example for the Node oder Node-Set with the ID 293.

Have you heard of this thermal mass and how the heat generation in dependence of the temperature can be included in the simulation?

Best regards,

Christopher

• peteroznewman
Subscriber

Hello Christopher,

Good find.  Here is the section of the ANSYS Help page for the MASS71 element that describes the function of temperature.

I suppose each node can have one of those elements and be connected to a set of elements that conduct heat across the domain.

Best regards,

Peter

• peteroznewman
Subscriber

Hello Christopher,

Attached is a model that puts one MASS71 element on each face of a thin body.

I could instead put a MASS71 element on each node, but that would be 16 edits instead of 9 and I was short on time : )

I haven't yet figured out how to write the code that puts the A1 - A6 coefficients onto those elements, so maybe someone in the community can help.

Best regards,

Peter

ANSYS 18.2 archive is attached.

• chris1992
Subscriber

Hello Peter,

I'm very thankful for your support. I will discuss your input with my colleagues next time. Simultaneously I'm trying to do this simulation with LS-DYNA and I think this is working quite well.

Best regards,

Christopher

• tianshixiang1993
Subscriber

Hello Chris,

Have you sovles the problem? I meet the same challenge as you in the setting of Ansys. Could you please share the solution if you overcome it?

• Kainze
Subscriber

Hi,

any advice how you use TEMP as a variable for the internal heat generation?

Best regards

Kain

• peteroznewman
Subscriber

Did you try to use MASS71 method shown above?