Learn how to run thermal simulations in Autodesk Fusion—from materials and loads to mesh, results, and reports.

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Thermal analysis is essential for validating design decisions when components will operate under specific temperature conditions. Whether you’re designing cooling fins, evaluating insulation performance, or ensuring materials can withstand operational heat, Autodesk Fusion’s simulation workspace provides the tools you need to model and analyze thermal behavior accurately.

This guide walks through a complete thermal simulation workflow using a practical example: analyzing an insulated pipe to determine if the chosen materials are suitable for its thermal operating conditions.

Accessing the simulation workspace

Fusion operates across multiple workspaces, each designed for specific tasks. While you typically work in the design workspace, thermal analysis requires switching to the simulation workspace.

When you first enter the simulation workspace, Fusion prompts you to select a study type. For thermal analysis, select Thermal Study and click Create Study.

The simulation workflow follows a logical left-to-right progression along the toolbar, guiding you through each step of the analysis process.

Simplifying your model (if needed)

Before running simulations, evaluate whether your model needs simplification. Complex features that don’t significantly impact thermal behavior can slow down computation without improving accuracy.

If simplification is necessary, use the simplify workspace to remove unnecessary details. For models where every component affects thermal performance, you can skip this step and proceed with the full geometry.

Assigning materials with thermal properties

Material selection is critical in thermal simulations. By default, Fusion uses the materials assigned in your model, but you can override these selections to explore different scenarios.

For an insulated pipe assembly, you might assign:

• Inner pipe: Copper (Wrought) for excellent thermal conductivity
• Middle layer: Polyurethane foam for insulation
• Outer jacket: ABS plastic for protection and structural support

When selecting materials from the Fusion database, pay particular attention to the thermal conductivity property. This value determines how readily heat transfers through each material and directly impacts your simulation results.

After assigning materials, the interface updates to reflect the material appearances, providing visual confirmation of your selections.

Applying thermal loads

Thermal loads define the boundary conditions that drive heat transfer in your simulation. You can apply these loads to entire bodies or individual faces, and a single surface may have multiple boundary conditions.

Applied temperature

The first load type represents direct thermal contact. For a pipe carrying hot fluid, apply a temperature load to the inner surface to simulate heat transfer from the fluid to the metal.

To select interior surfaces more easily, hide outer components in the model browser. This allows clear access to internal faces that might otherwise be difficult to select.

For a pipe carrying fluid at 95°C, apply this temperature to all interior faces. Because metal conducts heat efficiently and the fluid contacts the pipe directly, heat transfers by conduction from the fluid to the metal.

Convection loads

Convection represents heat transfer between a surface and the surrounding air. When a temperature difference exists between the outer jacket and ambient air, heat transfers through convection.

The rate of heat transfer depends on several factors:

• Surface geometry
• Material roughness
• Forced convection (such as fans or airflow)

These factors combine into a single convection coefficient value, typically measured in watts per meter squared per Kelvin (W/m²·K).

For ABS plastic, convection coefficients typically range between 5 and 25 W/m²·K. The specific value depends on your operating conditions. A value of 5 W/m²·K represents natural convection in still air, while higher values account for forced airflow.

You must also specify the ambient temperature, which affects the temperature gradient and heat transfer rate. For a room temperature environment, use 21°C.

Radiation loads

Radiation accounts for energy exchange between the object and its environment through electromagnetic waves. Unlike conduction and convection, radiation doesn’t require physical contact or a medium.

Apply radiation loads to exterior surfaces, specifying an emissivity value between 0 and 1. This dimensionless number represents how efficiently a surface emits thermal radiation compared to an ideal black body.

For ABS plastic, emissivity typically ranges from 0.92 to 0.95. As with convection, specify the ambient temperature (21°C in this example).

Establishing component contacts

Before solving, address any pre-check warnings. A common issue in thermal simulations involves component connectivity. For accurate heat transfer modeling, Fusion needs to understand how components connect physically.

Use Automatic Contacts to generate connections between components. In thermal simulations, contacts are limited to:

• Bonded: Components are perfectly joined with no thermal resistance
• Offset Bonded: Components are separated by a small gap with specified thermal conductance

If needed, access Manage Contacts to adjust thermal conductance values for specific contact pairs. This allows you to model thermal interface materials or imperfect contact conditions.

Establishing contacts satisfies the pre-check requirements and prepares your model for solving.

Mesh generation and refinement

Meshing divides your geometry into small elements for numerical analysis. Mesh quality significantly impacts both accuracy and computation time.

When you first generate the mesh, Fusion may display a notification that the mesh hasn’t been computed yet. Click Yes to generate and view the initial mesh.

To refine mesh settings, hover over the mesh option and click the pencil icon. Key settings include:

• Average element size: Controlled as a percentage (1-10%) of the model size. Smaller percentages create finer meshes with more elements.
• Per-part scaling: Adjust mesh density for specific components
• Absolute size: Specify exact element dimensions
• Advanced settings: Access additional controls for specialized scenarios

For improved accuracy in thermal simulations, consider reducing the average element size from the default to around 3%. This creates a finer mesh that captures temperature gradients more accurately, though it increases computation time.

Solving the simulation

Once materials, loads, contacts, and mesh are configured, click Solve to run the simulation.

You don’t need to wait for the solution to complete. Fusion runs simulations in the background, allowing you to continue working on other aspects of your design or set up additional study types.

To check progress, click Job Status to view the current state of your simulation. When complete, you’ll receive a notification and see a green checkmark indicating success.

Analyzing results

After solving, access the results section to explore your simulation outcomes. Fusion may take a few moments to fetch and display the results.

Temperature distribution

The default view shows temperature distribution across your model. This visualization uses a color gradient to represent temperature variations, making hot and cold regions immediately apparent.

Inspection tools

Fusion provides several tools for detailed result analysis:

Probes

• Minimum/Maximum probes: Automatically identify and display the coldest and hottest points
• Surface probes: Query temperature at any point on a surface
• Point probes: Measure temperature at specific XYZ coordinates, including interior locations

Cutting Planes

• Add planes along any axis to view internal temperature distribution
• Flip cut direction to examine different sections
• Combine with surface probes to measure interior temperatures
• Toggle visibility and cutting behavior independently

Range Controls

• Adjust the temperature scale using drag handles or numerical input
• Focus on specific temperature ranges of interest
• Highlight critical temperature thresholds

Heat flux analysis

Heat flux results show the rate of heat transfer per unit area, measured in watts per square millimeter (W/mm²). These results help you understand thermal performance and identify areas of high heat transfer.

You can view heat flux as:

• Total heat flux: Combined heat transfer in all directions
• Directional heat flux: Heat transfer along X, Y, or Z axes

Directional analysis is particularly useful for understanding heat flow paths through complex assemblies.

Thermal gradient

Thermal gradient indicates how rapidly temperature changes across your model. This metric helps identify areas of steep temperature change, which may indicate thermal stress concerns or opportunities for design optimization.

High thermal gradients can cause material stress due to differential expansion, making this analysis valuable for durability assessments.

Comparing multiple studies

To evaluate design alternatives, clone your study and modify specific parameters such as insulation materials, thicknesses, or operating conditions.

Use the Compare tool to view multiple studies side by side. This visual comparison makes it easy to assess how design changes affect thermal performance and identify the optimal configuration.

Generating reports

Professional documentation is essential for design reviews and regulatory compliance. Fusion’s report generation feature creates comprehensive documentation of your thermal analysis.

Click Generate Report and then Preview to view the report in your web browser. The report includes:

• Study setup and configuration
• Material assignments and properties
• Mesh settings and statistics
• Applied thermal loads and boundary conditions
• Results summary with visualizations

You can print the report directly or save it as a file for sharing with team members, clients, or regulatory authorities.

Best practices for thermal simulations

Material selection Always verify that material thermal properties match your actual components. Generic material properties may not accurately represent your specific materials, especially for composites or specialized alloys.

Convection coefficients The convection coefficient has a significant impact on results. Research appropriate values for your specific scenario rather than using default estimates. Consider whether your application involves natural or forced convection.

Mesh refinement Start with a moderate mesh density and refine in areas of interest. Extremely fine meshes increase accuracy but may not be necessary for all regions of your model.

Validation Whenever possible, validate simulation results against physical testing or known analytical solutions. This builds confidence in your modeling approach and helps identify potential setup errors.

Iterative analysis Use simulations iteratively throughout the design process. Early thermal analysis can identify issues when they’re easier and less expensive to address.

Conclusion

Thermal simulation in Autodesk Fusion provides powerful capabilities for analyzing heat transfer in your designs. By following this systematic workflow, from material assignment through results analysis, you can confidently evaluate whether your designs will perform as intended under thermal loading conditions.

The combination of intuitive tools, comprehensive material libraries, and detailed results visualization makes Fusion an effective platform for thermal analysis. Whether you’re designing consumer products, industrial equipment, or specialized thermal management systems, these simulation capabilities help you make informed design decisions backed by quantitative analysis.

Thermal simulation frequently asked questions (FAQs)