> ## Documentation Index
> Fetch the complete documentation index at: https://docs.ntop.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Thermal Connectors

Thermal connectors are typically used to enable heat flux between separate meshes in a model by thermally linking them. These are analogous to structural bonded contacts and tie constraints commonly used in structural stress analyses. Thermal connectors are necessary if there are multiple **Components**in the **FE Model**.

In heat sink applications, a thermal paste or an interface material fills microscopic imperfections and maximizes heat transfer between the mating surfaces of the heat source and heat sink. Thermal connectors conveniently model such interfaces.

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  <img src="https://files.learn.ntop.com/lessons/thermal-connectors/341_7_1-instructor_5u3dqlmop2xik78c9dl5vykpg_public_1647689493_re.1647689492262.png" />
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**Example:** an FE Model with a Thermal connector defined between two FE Components

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## Thermal Bonded Contact

Thermal connectors are modeled with a**Thermal Bonded Contact** block which enables heat flux between two components. As in other FEA tools, the thermal bonded contact is based on a master-slave formulation.

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  <img src="https://files.learn.ntop.com/lessons/thermal-connectors/341_7_2-instructor_5u3dqlmop2xik78c9dl5vykpg_public_1647689347_Connector.1647689345917.jpg" />
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The **Thermal Bonded Contact**block inputs are:

* \*\*\*Independent:\*\*\*Independent (master) mesh, with entities as Faces only

* ***Dependent:*** Dependent (slave) mesh

* \*\*\*Resistance:\*\*\*Resistance of the thermal bonded contact

* \*\*\*Tolerance:\*\*\*A suitable tolerance for the distance between the independent mesh and the dependent mesh to create the thermal bonded contact

* **Note**: Independent and Dependent meshes can be selected via:
  * **FE Boundary by Flood Fill**
  * **FE Boundary by Body**
  * **FE Face Boundary**
  * **Boundary by Body**

To learn more about meshing and selecting regions of a mesh, please refer to the [102: Guide to Meshing](/courses/102-guide-to-meshing/) course.

<Tip>
  **Tip:**
  Experimenting with different *Tolerance*values may help achieve optimal definition of the thermal bonded contact between two FE Meshes.
  Generally, the dependent (slave) mesh should have a more refined mesh.
</Tip>

## Resistance

\*Resistance (K/W)\*input in the **Thermal Bonded Contact**block is the reciprocal of thermal contact conductance (W/K), typically measured in experimental tests.