Thermal Contact¶

Introduction¶

Thermal Contact is used to model conductive heat transfer between two separate conduction bodies. This capability enables thermal coupling across interfaces where heat is transferred between adjacent solids through a prescribed thermal resistance model.

Thermal Contact can be used to represent direct solid–solid conduction, imperfect mechanical contact, thin interface materials, coatings, or reduced-order thermal connections between bodies. The resulting heat transfer depends on the temperature difference between the coupled bodies and the specified contact resistance properties.

The Thermal Contact object defines two coupled conduction regions, referred to as Body 1 and Body 2. Heat transfer is then computed across the interface connecting these bodies.

In the example below, two cylinders are in end-to-end contact. A thermal contact resistance is specified between the contacting faces. The initial temperature is 300 K. A 400 K boundary condition is applied to one end of the cylinder pair, and a 300 K boundary condition is applied to the opposite end.

Download Sample File: Thermal Contact

Heat flows from the high-temperature end toward the low-temperature end. Within each cylinder, the temperature profile decreases approximately linearly with axial position. The contact resistance produces a step decrease in temperature across the interface. The magnitude of this temperature jump is determined by the specified thermal contact resistance.

Property Grid¶

`Bodies`¶

Body 1: This specifies the first conduction body participating in the thermal contact model.
Body 2: This specifies the second conduction body participating in the thermal contact model.

`General`¶

Type

This defines the thermal contact model used to couple the two bodies.

Instant

Instant applies an idealized thermal connection between the two bodies with no explicit thermal resistance. Temperatures are coupled directly across the interface, resulting in effectively instantaneous conductive transfer.

2D

This applies a two-dimensional thermal resistance model across the contact interface. This model allows specification of interface resistance and effective conduction thickness for representing finite thermal transport between the coupled bodies. Within this model, interfacial heat flux is given by

\[q'' = \frac{\Delta T}{R}\]

where \(q''\) is the heat flux across the interface, \(ΔT\) is the temperature difference between the coupled bodies, and \(R\) is the thermal resistance. For a simple conductive layer, the thermal resistance is related to the material thickness and conductivity by

\[R = \frac{L}{k}\]

where \(L\) is the effective conduction thickness and \(k\) is the thermal conductivity of the interface material.

Resistance

K⋅m/W | This specifies the effective thermal resistance associated with the contact interface. Larger resistance values reduce conductive heat transfer between the coupled bodies, while smaller values increase thermal coupling.

Parallel Thickness

m | This specifies the effective conduction thickness associated with the thermal contact model. This parameter represents the characteristic distance over which heat is transferred normal to the contact interface.

The Parallel Thickness is used together with the specified resistance model to determine the effective conductive transport across the coupled interface. It is commonly used to represent thin conductive layers, coatings, or approximate wall thicknesses separating the two bodies.

Thermal Contact Output Data¶

Thermal contact output data between static bodies are saved in the Thermodynamics statistics file. These outputs, as part of the broader Thermal Output data, quantify the conductive heat exchange occurring across thermal contact interfaces.

Thermal Contact Toolbar¶

Context-Specific Toolbar Options	Description
Help	The Help command launches the M-Star reference documentation in your web browser.

For a full description of each selection on the Context-Specific Toolbar, see Toolbar Selections.