To simulate heat transfer through a hollow 3D geometry like a cone in COMSOL Multiphysics, you can follow these steps:

1. Create the Hollow Cone Geometry

• To create a hollow cone:Add a cone for the outer shell using the Geometry node. Add a second smaller cone to represent the inner hollow part and use the Difference operation to subtract the smaller cone from the larger cone.

2. Define the Material Properties

• Go to the Materials node and assign materials to the solid portion of the hollow cone.
• Ensure the material properties include thermal conductivity, specific heat, and density.

3. Add a Physics Interface

• Choose Heat Transfer in Solids from the Add Physics menu.
• Assign the domain to the heat transfer physics to specify where heat conduction will occur.

4. Set Boundary Conditions

• Inlet Temperature: Apply a temperature or heat flux at the inlet boundary of the hollow cone.Go to the Physics node, select the inlet boundary, and set the temperature or heat flux value.
• Outlet Boundary: Apply a boundary condition at the outlet to measure the heat flow.Use a temperature or heat flux boundary condition at the outlet.

5. Mesh the Geometry

• Use the Mesh node to generate a suitable mesh for accurate simulation.
• Ensure finer mesh elements near the inlet and outlet for better resolution.

6. Set Up the Study

• Choose a Stationary or Time-Dependent study depending on whether you need steady-state or transient results.
• Run the study to solve the problem.

7. Post-Processing

• Use the Results node to plot the temperature distribution along the cone.
• To measure heat passing through the outlet, use Derived Values > Surface Integration to calculate the total heat flux.

Troubleshooting

• If the simulation is not running as expected, check:Geometry: Ensure the cone is properly hollow. Physics Assignment: Verify that the domains and boundaries are correctly assigned to the heat transfer physics. Mesh Quality: Use a finer mesh for better accuracy. Boundary Conditions: Ensure the inlet and outlet conditions are applied to the correct surfaces.

Mehran Sharifi thanks for you reply but for some reason i am not able to set boundaries for input and output.

First, the geometry must be created carefully, taking into account the external and internal boundaries of the object. This can be accomplished by using logical operations to subtract the internal volume from the external volume. Ensuring that the geometry accurately represents the physical object is essential for reliable results.

Second, defining the materials is a vital step in the simulation workflow. Each region of the hollow structure may consist of different materials, each with its own specific thermal properties. Correctly assigning materials to the corresponding regions of the geometry is also critical for accurate heat transfer simulation.

After the materials are assigned, boundary conditions must be defined to simulate the thermal environment around the hollow structure. Boundary conditions define how heat interacts with the geometry surfaces. Common boundary conditions include constant temperature, heat flux, and convection to the surrounding environment.

The next step involves setting up the physics to simulate heat transfer. For hollow geometries, heat transfer by conduction is often dominant. The heat transfer interface can be activated to include conduction within the solid and include appropriate options for convection and radiation, if required.

After configuring the physics settings, the mesh generation process begins. A fine mesh is critical to accurately capturing heat transfer gradients, especially in areas where rapid temperature changes are expected, and you can thicken the mesh in the selected area to get accurate results and save time.. The laptop has a big impact on the number of mesh elements.

Once the mesh is optimized, the simulation can be executed.