Thermal Simulation in Fusion

By Admin, 16/07/2026 · 3 min read

Set up a steady-state thermal study in Fusion, apply realistic heat-transfer conditions, refine the mesh and check the result.

Fusion simulation

Thermal Simulation in Fusion

Set up and check a steady-state heat-transfer study using a finned heat sink as the worked example.

Watch Autodesk's thermal simulation walkthrough

Study

What the model answers

A steady-state thermal study estimates temperatures after the system has settled. It does not show warm-up time. The answer depends on material conductivity, heat input, thermal contacts and how heat leaves the model.

Demo settings

Heat source: 20 W internal heat on the orange source body.

Cooling: convection on every air-exposed heat-sink face, with Ambient Temperature = 25 C. Enter the heat-transfer coefficient supplied for the real airflow; do not reuse an arbitrary value.

Contact: bonded contact between the source and heat sink for this simple demonstration. A real pad or adhesive needs its measured thermal conductance.

Finned heat sink thermal simulation setup

Tutorial

Fusion thermal simulation steps

Open each image to view the Fusion controls at full size. The Applied Temperature panel is included for models with a genuinely controlled-temperature face; the 20 W heat-sink demo instead uses Internal Heat.

Create a Thermal study

Open the model, change the workspace from Design to Simulation, then choose New Study > Thermal > Create Study. A thermal study predicts how heat moves through the model after temperatures have settled; it does not calculate how long warming takes.

Assign the study materials

Choose Setup > Materials > Study Materials and assign each real material. Thermal conductivity describes how easily heat passes through a material: a high value spreads heat quickly, while a low value acts more like insulation. Density and specific heat mainly matter when temperature changes with time; conductivity is central to this steady-state study.

Add the heat input

For this heat-sink demo, choose Setup > Loads > Thermal Loads > Internal Heat, select the source body and enter 20 W. A watt is one joule of energy transferred each second. Applied Temperature, shown here, should be used only when a real face is maintained at a known temperature.

Describe cooling to air

Choose Setup > Loads > Thermal Loads, set Type to Convection, and select every air-exposed surface except the source contact. Convection represents heat carried away by moving air or liquid. The heat-transfer coefficient states how strongly that fluid removes heat, so use a value that matches natural airflow, forced airflow or liquid cooling.

Mesh and solve the model

The mesh divides the solid into small finite elements that Fusion solves together. Smaller elements capture steep temperature changes more accurately but take longer to solve. Choose Generate Mesh, then use Local Mesh Control at contacts, fin roots and other areas where temperature may change quickly.

Read and verify the result

Temperature shows how hot each location becomes. Heat flux shows the rate and direction of heat flow through an area, while a temperature gradient describes how quickly temperature changes over distance. Probe the hottest point, inspect the heat path, then refine the critical mesh until the important values change only slightly.

Checks

Before using the result

Confirm that the hottest location makes physical sense, contacts are complete, and the imposed heat has a realistic path to ambient or a controlled-temperature boundary. Compare a known temperature or hand calculation where possible.