Thermal Contact Resistance - MapleSim Help
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Thermal Contact Resistance

Basic thermal contact resistance between two materials

 

Description

Equations
 
Fundamental equation is:

References

Variables

Connections

Parameters

See Also

Description

The Thermal Contact Resistance component models a heat transfer between two materials which have different thermal conductivities.
The following image illustrates an example of apparent contact area of two materials.

        

Because of the surface roughness of both materials, the actual contact area of two materials becomes spots of contact. The other areas are regarded as the void space filled by fluid such as air. The following image illustrates the mechanism of jointed surface in more detail.

        

Then heat flow of the contact of two materials is regarded as the following image. This component is based on this.

Using each option, you can control the apparent area size, area ratio, and the thickness of void space by real input signals.That makes it possible for you to change contact resistance value during simulation. For example, change by deformation of actual contact area size caused by joint pressure change.

Equations
 
Fundamental equation is:

The equation for the areas is shown below:

The equation for heat flow is as below:

 

References

[1] : J. P. Holman. "Heat Transfer Ninth Edition", McGraw-Hill Higher Education.

Variables

Symbol

Units

Description

Modelica ID

Heat flow rate from port a to port b

Q_flow

Temperature difference between port a and port b

dT

Thermal contact resistance

Rc

Coefficient of thermal contact conductance, which is the inverse of Rc

hc

Apparent contact area

A

Ac

Area of void space

Av

Thickness of the void space

L

Connections

Name

Condition

Description

Modelica ID

 

Thermal port a

port_a

 

Thermal port b

port_b

if use Apparent contact area input is
true.

Apparent contact area is defined by Real signal input.

A_input

if use Area ratio input is
true.

Area ratio  is defined by Real signal input.

Aratio_input

if use Void space thickness input is
true.

Thickness of the void space is defined by Real signal input.

L_input

Parameters

Symbol

Default

Units

Description

Modelica ID

Solid material property data

Material_a

Material_a.k is the thermal conductivity of the material of port_a

Material_a.k

Material_a.cp is the specific heat capacity of the material of port_a

Material_a.cp

Material_a.rho is the density of the material of port_a

Material_a.rho

Solid material property data

Material_b

Material_b.k is the thermal conductivity of the material of port_b

Material_b.k

Material_b.cp is the specific heat capacity of the material of port_b

Material_b.cp

Material_b.rho is the density of the material of port_b

Material_b.rho

The thermal conductivity of the fluid which fills void space

kf

Apparent contact area between materials

A_const

Area ratio  (between 0 and 1)

Aratio_const

Thickness of the void space

L_const

See Also

Heat Transfer Library Overview

Basic Overview


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