# Session 2 Step-by-Step Tutorial - Heat Transfer Analysis of a Cooling Plate

#1

## Homework Submission

For your homework, your task is to set up a heat transfer simulation of a cooling plate to determine the resulting temperature and heat flux distribution. Since there are temperature sensitive IGBT components on one side of the cooling plate it is important that all surfaces of the cooling plate remain below 115 degrees C.

The step-by-step tutorial below contains all of the steps for setting up the simulation in SimScale and visualizing the results.

Homework Deadline: Sunday, December 24th, 11:59 pm CET

## Outline

PART 1:

1. Introduction

2. Project Import

3. Mesh Generation
a. Automatic Meshing

4. Simulation Setup
a. Domain
b. Material
c. Boundary Conditions
d. Numerics
e. Simulation Control
f. Simulation Runs

5. Post-Processing
a. Filters/Visualization

## Introduction

Because of the high power density of electric motors, the selection and design of the cooling system has a big influence on the performance and efficiency of the electric motor in a Formula Student race car. Optimizing the cooling system can lead to a significant improvement in the overall performance.

To prevent temperature build-up, a cooling plate can used to pull heat from the motor. The cooling water flows through channels in the plate acting like a heat exchanger.

A heat transfer analysis can be done to analyze the temperature and heat flux distribution of the cooling plate.

Cooling Plate Specifications (courtesy of eMotorsports Cologne):

Heat output: 1600W (400Wx4) for 80kW engine power
Nominal heat output: 984W (246Wx4)
Maximal water temperature @inlet: 60Â°C
Maximal IGBT temperature (IGBT are the parts which are on the cooling plate): 115Â°C
Material: aluminum

## Project Import

To start this exercise, please click on the link below and then make a copy of the project.

https://www.simscale.com/projects/AnnaFless/cooling_plate_1/

## Mesh Generation

In the Mesh Creator tab, click on the geometry Cooling Plate

Then, click on the New Mesh button in the options panel.

Select Tet-Dominant mesh. We will leave the default meshing settings for the first 4 settings: Automatic for Element Sizing, 2-Coarse for Mesh fineness, First order under the Element order, and then change the Number of computing cores to 8.

This operation will automatically create a mesh for the geometry. The cell size and refinement will be adapted automatically.

Click on the Save button to save all settings.

Now click the Start button to begin the mesh operation. The meshing job will start in a few moments. You can see the status of the mesh in the bottom left corner of your screen.

The mesh operation takes about 10 minutes to complete.

### Simulation Setup

For setting up the simulation switch to the Simulation Designer tab and select New simulation.

A pop-up window will appear allowing you to choose the analysis type for the simulation. Select Heat Transfer - the Heat Transfer analysis type is used to determine the temperature distribution and heat flux in a solid body.

Note: For the heat transfer analysis type, only thermal changes are assumed. No mechanical changes are taken into effect (ie stress or deformation)

Click Create to apply the analysis type selection.

In the properties section, leave the default values of Steady-State and false for Nonlinear analysis

### Domain

The green check marks on the items in the Navigator refer to saved states whereas the red entries denote fields with missing data that must be filled in.

Click Domain from the tree and select the mesh that you created. Click the Save button. The mesh will then automatically load in the viewer.

Change the render mode to Surfaces to interact with the mesh more easily.

### Topological Entity Sets

In order to make the simulation set-up easier in following steps, we will first create Topological Entity Sets. TES allow us to assign certain faces or volumes to a group.

#### Master TES

Hide the top solid of the cooling plate by clicking on the eye in the scene tree

In the viewer, select the top faces - these are the faces that will be in contact with the solid that is hidden. We will use this TES for setting up the bonded contact in the next step.

Once youâ€™ve selected the faces as shown, click on Create Set

Name the set: Master and click Create

There should be 17 faces selected.

#### Slave TES

Now, hide the bottom part of the cooling plate and show the top part. We will now set up the TES for the other side of the contact between the parts.

Select the faces (17 faces) that will be in contact with the solid that is hidden. When this is done, Create set and name the set Slave

Click Create

#### Top plate convection TES

Keep the top plate in the viewer. We will now create a topological entity set for the faces where the water convection boundary condition will be applied.

Carefully select all of the bottom and side faces in the channel. A single click will select the face. Similarly another click will unselect a face if you make a mistake and need to correct it.

Once you have selected the faces (133 faces in total) of the channel, create the set and name it Top-plate-convection

#### Bottom plate convection TES

For the final TES, hide the top plate and show the bottom plate. Similarly, carefully select all of the bottom and side faces of the water channel

Once you have selected the faces (155 faces in total) of the channel, create the set and name it Bottom-plate-convection

### Contacts

Since the cooling plate consists of two solids, we need to setup a contact so that the solver knows that the solids are connected.

A bonded contact is a special type of contact which allows no relative displacement between two connected solid bodies. This type of contact constraint is used to glue together different solids of an assembly. The two surfaces that are in contact are classified as master and slave. Every node in the slave surface(slave nodes) is tied to a node in the master surface(master node) by a constraint. Read moreâ€¦

Go to Contacts in the Navigator and Click New.

Name the contact Bonded Contact. Then assign the Master Topo entity set to the Master Entity (TIP: to select the assignment, click on it in the Scene Viewer)

and the Slave set to Slave Entity

Click Save to preserve your settings

### Select Solid Material

Now we will define the material for the front upright. Select Material in the Navigator and click New.

Click on Import from material library to import the desired material from the material database.

Select Aluminum and click Save.

Click on your model in the viewer. You should now see the entire Volume assigned under Assignment

Click Save in order to define the material for this region.

### Boundary Conditions

In this section, we will define the thermal loads for our simulation case. This is one of the most important parts of the simulation set-up.

In this case, there are no Temperature Loads. Go to Heat Flux Loads and click New

A new boundary condition with a default name will be created. Rename it to Surface heat flux.

Under Type select Surface heat flux and set q = 70000 W/m2. (q is the amount of heat transferred (heat flux))

Assign the Boundary Condition to the four faces that are exposed to the heat sources and click Save.

Next, we will add another Heat Flux Load. Go to Heat Flux Loads in the tree and click New

A new boundary condition will be made under Heat Flux Loads. Rename it to Outer convection

Set the Type to Convective heat flux and apply a reference temperature of 300 K and h value (heat transfer coefficient) of 10.

Assign this BC to all of the outer faces of the cooling plate - ie the faces that are exposed to air with the exception of the heat sources. There should be 18 faces in total. Finally click Save.

A new boundary condition will be made under Heat Flux Loads. Rename it to Water-Convection

Set the Type to Convective heat flux and apply a reference temperature of 330 K and h value (heat transfer coefficient) of 1500.

First add the Bottom-plate-convection and Top-plate convection to the Assignment.

Then hide the top plate, we need to add 3 more faces near the inlet/outlet:

and 3 more faces at the opposite inlet/outlet

There should be 294 faces in total. Finally click Save.

### Simulation Control

Next we will move to the Simulation Control item in the project tree to define the parameters we want to use to run the simulation.

The number of computing core needed to run a simulation is highly dependent on the size of the model (number of nodes). In this case, 4 computing cores is sufficient.

Leave the maximum runtime set to the default value of 3600 s. This parameter rarely needs to be changed for heat transfer simulations due to the low computing power required.

### Result Control

Result Control allows us to define extra simulation result outputs. In addition to temperature, we will add heat flux.

Right click on Solution Field and click Add Solution Field item

Set the Name to Heat flux; the Type to heat flux and the Heatfluxtype to heat flux field

Next, from Result Control, we can add area calculations to show us the minimum and maximum temperature on the top plate and bottom plate.

Click on Result Control and the New for Area calculation

Set the name to top plate temperature; Type to minimum and maximum; Field Selection to temperature; and component selection to Temperature

Assign the result control item to the face of the front plate

Next, use the same procedure to add an Area calculation for the bottom plate

### Create New Run

Click on Simulation runs and create a new run by clicking on New.

The final step is to click Start. Your simulation is now computing in the cloud.

### Post-processing

Once the simulation is finished (this will take about 3-4 minutes), go to the Post-processor tab to view the results.

Select Solution fields of Run 1

Temperature Field:

Heat Flux Field:

Based on the surface temperature, will the surface be safe for placement of the IGBT components?

## Homework Submission

Homework Deadline: Sunday, December 17th, 11:59 pm CET

#4

Hi, I was wondering if the webinar was recorded/uploaded on YouTube. Thank you very much for all your work.

#5

Hi @framsis!

Best,

Jousef

#6

Hi to All,
I have some issue with topological entity set - Master vs. Slave, I try to do my best but I picked only 11 faces for each component, but accordingly to the tutorial the faces on both componet could be 17. What do I wrong?

This is my project https://www.simscale.com/projects/DobesJ/cooling_plate/

Thank you

#7

Hi,

Any tips when defining the TES for the channel? I can only seem to find 130 out of the 133 faces.

Panos

#8

Hi Panos,
I fought with same issue, but the faces for TES is really 133, some small radiuses are divided to the two faces, that maybe a little tip.

#9

Hi,

Iâ€™ve checked all the radii on the two symmetrical parts where thereâ€™s a lot of them, but I didnâ€™t find any I missed before. Are you referring to a specific part of the model?

Thanks for the help,
Panos

EDIT: I found out I was missing some of the side faces, some straight pieces, duh!

#10

Hi @DobesJ!

Did you figure it out already or do you still need a hand on this?

Best,

Jousef

#11

Hi,
In my opinion the link of the homeworkâ€™s submission of the past lesson didnâ€™t work because I didnâ€™t receive the email confirmation.
So today I sent with the link of the second email of the second tutorial both of my homeworks of the two sessions and Iâ€™ve already received the email confirmation.
Sorry but I only wanted to report you this problem.
Thank you.

#12

Itâ€™ s happened same to me, and Iâ€™ve re-submitted all the homework today

#13

I contacted my colleague @AnnaFless and she will clarify this asap. Sorry for the confusion and the lost time so far. If you need any help please feel free to contact me privately if you like.

Cheers and all the best!

Jousef

#14

As long as you received a message on your screen that the submission was successful you are fine! Hope that clears up things a bit. Sorry for any inconvenience caused.

Best,

Jousef

#15

Hello again,

The link for the homework submission leads to the one for the 1st session. Can we get the right link somewhere?

PNtakos

#16

Hi @PNtakos,

The link has been updated so you can submit for the 2nd session.

Cheers,
Anna

#17

Hi, I got a lower temperature range (for both maximum and minimum) for the whole domain and I am wondering if anyone else got the same result.

My TES matched the tutorial, and I double checked on the loading conditions, used automatic meshing. Thank you.

#18

#19

Hey community,

I am not able to select anything in order to create a Topological Entity Set in the Simulation Designer after a assigned the created mesh to Domain and selecting â€śpick facesâ€ť. What could be the reason for this? Even I had the problem just to find 11 faces for the Master Topological Entity Set a few days before.

Thank you very much.

#20

If the mesh already finished you need to delete the results by rightclicking on the mesh. You may then proceed with assigning the faces and make further refinements. Let me know if it worked!

All the best!

Jousef

#21

Thank you for taking the time to check Arpan, my temperature ref. value was 300K, I changed it, ran the simulation again and got the expected results. Thank you.

#22

Hey,
I completed the assignments but i still havenâ€™t received a certificate, was there anything wrong with my hw?