Thermal Resistance definition for thermal contact

July 31st, 2009


In thermal analysis of assemblies, SolidWorks Simulation lets you define thermal contact resistance values. This allows you to model the thermal effect of a layer of a material which is too thin to mesh in 3D. However, the user needs to input the value of the resistance. Here is a primer on how to calculate the thermal resistance:

glue-layer2

The expected value is either the total or distributed resistance, respectively in K/W or (K.m²)/W in the SI unit system.

The basic formula for temperature drop in a thin layer of material between two parts is given by:

DT = q * [t / (k * A)]

where:

DT= temperature drop at the contact zone in K

q = heat power flowing through the contact in W

t = thickness of the layer in m

k = thermal conductivity of the layer material in W/(mK)

A = surface area of the contact in m²

 

The total thermal resistance is t/(k*A) and the distributed resistance is t/k.

heat-flow2

Thermal conductivity required to have a given thermal resistance

You can also determine the thermal conductivity required to have a given thermal resistance.

For a material of constant thickness, the total thermal resistance is Rt =  t/(k*A) and the distributed resistance is Rd = t/k.

With:

t = thickness of the layer in m

k = thermal conductivity of the layer material in W/(mK)

A = surface area of the contact in m²

Therefore, you can calculate the required thermal conductivity k to use in a material of thickness t to have the thermal resistance you need: k =  t/(Rt*A) or k = t/Rd.

Vikram Vedantham

Simulation Product Manager 3DVision Technologies

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One Response to “Thermal Resistance definition for thermal contact”

  1. tushar says:

    we are the student at MSU,in final year of BE-4(mechanical). We doing project on thermal contact resistant i.e. whats the effect of pressure, surface roughness etc. we kindly need your help in our project.Hoping you will help us and reply soon.

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