Learning Forum

[tandinhtamky]

Hi there,

My simulation is cooling battery cells with the air.

Almost thing seems fine, except gradient of temperature of battery. From surface of cell to core (outter to inner), it should be increase of temperature. Here I see is the same temperature.

[tandinhtamky]

Please help me, because this is my thesis

[Rob]

What boundary conditions are you using on the battery?
As an aside, bumping a thread after 48 hours is reasonable, after an hour isn't. The community will get to your query, but bumping too quickly also resets all of the monitors.

[tandinhtamky]

Thanks for replying me.
I'm sorry about that. It's will not happen in the next time.
About boundary condition, now I have a simpler simulation, just 2 cells and fluid domain, below is boundary condition.
About wall, I setup almost default.
Here is a result.

[DrAmine]

How are you modeling the two "cylinders"? Are they resolved? Are you putting there a source term for energy?

[tandinhtamky]

Yeah, here is it

[DrAmine]

And the interface connection is correct? If you make a heat flux report: what do you see? Add a screenshot.

[tandinhtamky]

hmmm i don't know exactly what heat flux report is ... Isn't it

[Rob]

Where is contact_cells_fluid-src ? Given that's probably linked to wall-12 and/or wall-13 there's something wrong with the boundary conditions.

[DrAmine]

or wall-4 and its shadow: please list the interface connection and add a screenshot!

[tandinhtamky]

Here is new.

[Rob]

Changing the model isn't overly helpful when trying to figure out what's going on. Where are the interface zones?

[tandinhtamky]

In a capture above, interface zones is intf:01:wall-cells::wall-fluid_domain, which is between fluid_domain and battery cells.

[Rob]

Which aren't passing heat. Use Share Topology in the geometry, remesh and try again. I think the interface zone isn't set up right, isn't really needed, and is blocking heat from leaving the battery.

[DrAmine]

Bit weird but I also think that is due to interface I see it is exchanging heat, though. But your second screenshot has now nothing to do with your first one: check now the temperature field.

[tandinhtamky]

Thank you for replying me.
My process is draw in solidwork, export .step file, import to Geometry. That's all, I do not adjust anything in Geometry in Workbench.
In the Meshing, beside create a mesh, create name selection, I check the contact between surfaces. Almost automatic.
What I find strange is, if heat not transfer, why fluid_domain has a increase in temperature? Beside of that, at the battery_holder (contact to cells), I still have a temperature change, like image below.
In the image, 3 cells with battery holder at the top of cell. I don't know where I were wrong.
Also, in the 3 cells, a middle cell I don't setup a heat source, and temperature result show like this.

[Rob]

Except you've shown two or three sets of results. In some the fluid warms up, in others it doesn't. We then have flux reports which may or may not link to the images.
Re the modelling approach. Building CAD elsewhere is good practice if you have the tools, and is why Ansys software is CAD agnostic. However, you do need to do a share topology step in the Ansys CAD (SpaceClaim usually) so we don't have too many interface zones. That means the mesh is conformal (no interface zones) and makes the set up much simpler.

[tandinhtamky]

Thank you so much, Sir.
I followed your instructions, I used share topology in spaceclaim. But it not working.
Next, I followed this video, about conjugate heat transfer. I follow method 3 in this video, but it is still not working.
So, do you have any other solution, Sir :(

[Rob]

Share Topo isn't working? Or the mesh isn't? Or heat isn't being transferred? Start by checking the geometry, post pictures. Then the bc's and mesh, a slice through the domain showing full cells please. Then show heat transfer and flow field. I need enough to understand what's going on. Make sure this is for ONE model as debugging two at once isn't going to end well.

[tandinhtamky]

In boolean, option "preserve tool bodies" --> yes.

[tandinhtamky]

Interior-cell domain & Interior-cell domain-shadow: Coupled Thermal.
Methods: Coupled.
Controls: default.
Steady steate.

[tandinhtamky]

Result:

Thank you so much, Sir !!

[Rob]

See how easy it is once you know how :) Good to see it's all working.

[tandinhtamky]

Thank you for your patience ! Have a nice day, Sir.