Busbar Thermal Analysis - Ansys Maxwell & Icepak - One and Two-Way Coupling

Busbar Thermal Analysis - Ansys Maxwell & Icepak - One and Two-Way Coupling Hello everyone, in this video I'm going to show how to link Ansys Maxwell and Icepak together for both a one-way and two-way coupling setup, and then we'll compare the results.

The model that I'm using is the DC conduction solver example. You can find it by clicking Open Examples, Maxwell General, DC conduction, and it's the first design in this project. I've copied that design into a new project that I've renamed, and I went ahead and ran it. This runs extremely quickly.

We can see that it only took about 12 seconds. I can now go ahead and plot the results of this. I guess before I do, I'll mention how this is set up. This is a busbar that has, you can see, several different current terminals, current excitations.

These are all given 1 amp each, pointing into the busbar, and then there's a sink on this other end for the current to flow out of.

Here we can see the voltage on the busbar, the ohmic loss, which is important, this is what's going to be sent over to Icepak, and we can also see the surface current density vectors. Now I'm going to set up the one-way coupling design. Right-click on the Maxwell design, click Create Target Design.

I'm going to do a natural convection, grab the vectors in the minus Z, and everything else is already ready. As you can see, this automatically creates the Icepak design. This already has the EM losses imported from the other design.

We can see that they have been applied to this volume, which, of course, it already brought over the model. This is the Solution Data tab, and keep an eye on how things are progressing, both in the profile and the residual time, and click the tab.

And there we go, we can see the residual for all these different velocities starting to converge. Now that it's done, I'm going to plot a couple of values. So first, I'm interested in seeing the temperature. Right-click on the model, plot fields, temperature, and I'll plot on the surface.

Here we can see the temperature on this thing; it's like pretty uniformly 52 degrees, but there is, of course, a gradient across it that we would expect to see. Next, I'd like to see the temperature of the ambient as well, so I'll just plot that on a plane.

I'll click this global XZ, right-click, plot fields, and the same thing, temperature. There we go. Now we can see, of course, the max temperature is going to be on the model itself, 52.8 degrees. We'll keep that in mind for later. Let's now set up the two-way coupling example.

So first, we need to go back to the Maxwell side, and we need to add a thermal modifier to the conductivity of this copper material in order to be able to even enable the temperature feedback. So, to do that, right-click on the material, click Properties, and View, Add or Edit Materials.

This is a copper that I made using this value for my bulk conductivity. On the right, click View/Edit Modifier for Thermal Modifier. And for the bulk conductivity's thermal modifier, drop that down and click Edit.

This pops up a box where we can add a thermal modifier a couple of different ways, either as an expression, as you can see here, using some logic, or a temperature-dependent dataset, or as a quadratic, which is what we're going to be doing here.

So, for copper, and the temperature range that I'm operating in, I'm going to be using these coefficients. I calculated these values by fitting a quadratic to some experimental datasets.

I'll be releasing a companion video to this one explaining that whole process, which you should be able to find a link to in the description. So, moving on from here, let's click OK. You should now see that the thermal modifier for our material, this copper, is now defined.

Up at the top, Maxwell 3D, let's set Object Temperature and check the box for Include Temperature Dependence and Enable Feedback. All of these boxes that have Temperature Dependent checked are that way because we just set a thermal modifier in this material.

I'll leave all of these set to 22 degrees Celsius. And this is now ready to set up the two-way coupling design. So, again, I'm going to right-click and Create Target Design. Natural convection. Click OK. Let's rename this to a coupling.

And this time, let's right-click on the analysis and add two-way coupling. I want to do maybe five iterations, just to make sure that it's reached a steady-state value, and click OK. We've now set up the two-way coupling and are ready to run this analysis.

Already, we can see that there's a higher maximum temperature in the case of the two-way coupling compared to the one-way coupling. Here, we see a max temperature of 56 degrees. In the one-way coupling example, we saw that the maximum temperature was 52.8 degrees.

This difference makes sense if you think about what's happening with the two-way coupling versus the one-way coupling. The temperature from Icepak in the two-way side is getting pushed back to Maxwell and updating its thermal conductivity.

We know that conductivity is going to decrease if the copper is warmer, which means the resistivity is going to increase. Having higher resistivity means more ohmic heating for the same applied voltage or current distribution.

And more heating means it's going to push the temperature even further up in Icepak, and the cycle is going to repeat until it converges, or however many iterations we set, in this case, five iterations. That's it for this one. I hope that this was helpful.

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