# Thermal Analysis in SOLIDWORKS Simulation Using a Microchip as an Example

Did you know that the multifunctional Simulation module can solve thermal research problems? It not only allows you to see how the temperature spreads over the parts, but also makes it possible to find out how long the part heats up. All this and much more – in our article.

### Introduction

A microchip assembly was taken as a model, which consists of a heat sink (bottom) and the chip itself (top) – Fig. one.

By adding Simulation module into the SOLIDWORKS interface, create New research and choose Thermal analysis… We have loaded the research tree, in which we can set the settings for the analysis (Fig. 2).

I must say right away that if you prefer watching lessons to reading educational materials, welcome to our YouTube channel. “SOLIDWORKS School”… By link you will find a video where we learn how to conduct a thermal study in SOLIDWORKS Simulation and set various thermal loads such as temperature, heat output and convection

### Material assignment

The first thing we need to do is set the material. Right-click on one of the parts and click Apply / edit material… In our example, we will choose aluminum for the heat sink, namely Alloy 1060… Let the material for the chip be galvanized steel. You will need to specify the thermal conductivity – such mandatory parameters are highlighted in red in the opening table (Fig. 3). Copy the “galvanized steel” into a folder User customized material and add thermal conductivity to the material: 50.

### Setting boundary conditions

For the convenience of setting the boundary conditions, let us separate the chip and the heat sink from each other. To do this, go to the tab Configurations (Fig. 4) and by clicking the right mouse button, add New view with exploded parts… Choose in the settings what exactly we want to shift. By pulling the arrow, we perform the offset. And press the button Apply

The next step is to set the thermal power of the microchip. Right click on the button Thermal loads and go to the heat output settings. Let’s select the entire “Chip” element in the assembly tree and indicate 15 watts (Fig. 5). Heat will be generated from this element.

Next, we set a set of contacts. To do this, right-click on the button Connections, choose the type of contact Thermal resistance and indicate the edges where the chip and the heat sink are in contact. We set the thermal resistance equal to 2.857e-6 K / W.

Now we will reconnect our parts through the tab Configurations and proceed to the definition of the convection of these parts. With the right mouse button, select Thermal loadsand then open the menu Convection… We select the edges of the heat sink that do not touch the heating chip.

We set the coefficient of convective heat transfer: 200 W / m2K. This coefficient characterizes the intensity of heat transfer between the surface of the body and the environment. We indicate the mass ambient temperature, that is, the temperature that surrounds our model. For this parameter we will set 300 K (Fig. 6).

We will do the same for the chip. We select the outer edges of the chip, set the convective heat transfer coefficient equal to 90 W / m2K, and the mass ambient temperature, as in the previous case, is 300 K.

### results

Let’s start the study (Fig. 7). By default, the mesh will be built automatically.

The study is completed, you can see the temperature distribution. To do this, select the parameter Section limitation along the plane “to the right” (Fig. 8).

Now we can see how the temperature spreads from the chip along the heatsink (Fig. 9).

If we want to know how long it takes for the heat sink to heat up, we need to set a transient process. To do this, we will copy our research (Fig. 10).

By clicking on the study with the right mouse button, let’s go to its properties (Fig. 11).

Let’s change the solution type to Transient process… Let’s indicate the total time (for example, 100 seconds) and set a five-second time interval (Fig. 12).

A non-stationary thermal study now requires the use of an initial temperature. We choose the temperature in Thermal loads and set the initial temperature for all bodies: 22 ° C (Fig. 13).

We launch the solution. Having received the result, we can see the temperature distribution and its value at the selected time (Fig. 14).

### Output

The SOLIDWORKS Simulation Engineering Module allows you to perform thermal analysis, analyze temperature propagation in parts, investigate temperature changes over time, and more. If you want to simulate heat flows that come from parts, you need another module: SOLIDWORKS Flow Simulation. But we will tell about it next time.

Author: Maxim Salimov, Technical Specialist for SOLIDWORKS, CSoft Group. email: salimov.maksim@csoft.ru