Aligned Carbon Nanotube Adhesive for Radiator Thermal Choke

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Solution Overview

Problem

There is an inefficient thermal transfer between the face-sheet and the heat-pipe in spacecraft radiator panels due to interface impedance, leading to a thermal choke that hampers effective heat dissipation from electronics to outer space.

Innovation Solution

A thermal conductive joint is introduced between the face-sheet and the heat-pipe, comprising an adhesive layer with carbon nanotubes (CNTs) oriented axially and in physical contact, acting as a thermal bridge to enhance heat conduction from the face-sheet to the heat-pipe.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a conventional adhesive layer is used to join the face-sheet and heat-pipe, then the structural bond is achieved, but the thermal conductivity at the interface is insufficient causing thermal choke

Engineering Contradiction:
Improvethermal conductivityVSAvoidheat transfer efficiency
Core Design Contradiction:
TemperatureVSLoss of energy

Solution Approach 1:

The adhesive layer is enhanced by incorporating carbon nanotubes (CNTs) to create a composite material that combines the bonding properties of the adhesive with the high thermal conductivity of CNTs. This composite structure allows the joint to maintain both structural integrity and superior thermal transfer capabilities, eliminating the thermal choke effect while preserving the structural bond function.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The thermal conductivity parameter of the adhesive layer is dramatically improved by adding CNTs, which have exceptionally high thermal conductivity along their axial direction. This parameter change transforms the adhesive from a thermal barrier into an efficient heat conduction path, resolving the contradiction between maintaining bond strength and achieving thermal conductivity.

Inventive Principle:
Principle #35Parameter changes

2Loss of energy

If the adhesive layer is made thinner to reduce thermal resistance, then heat transfer improves, but the bonding strength and structural integrity may be compromised

Engineering Contradiction:
Improvethermal resistanceVSAvoidbonding strength
Core Design Contradiction:
Loss of energyVSStrength

Solution Approach 1:

By creating a composite adhesive layer with CNTs, the material achieves high thermal conductivity without requiring the layer to be extremely thin. The CNTs provide thermal conduction pathways that allow efficient heat transfer through a layer of sufficient thickness to maintain bonding strength and structural integrity.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The CNTs are oriented axially within the adhesive layer to create localized high-conductivity pathways for heat transfer. This local quality enhancement allows the adhesive layer to have varying properties: sufficient thickness for bonding strength, but with concentrated thermal conduction channels provided by the aligned CNTs.

Inventive Principle:
Principle #3Local quality

3Temperature

If carbon nanotubes are added to the adhesive layer to improve thermal conductivity, then heat transfer efficiency increases, but the manufacturing complexity and alignment precision requirements increase

Engineering Contradiction:
Improvethermal conductivityVSAvoidCNT alignment precision
Core Design Contradiction:
TemperatureVSManufacturing precision

Solution Approach 1:

The manufacturing process is designed to control the orientation parameter of CNTs during adhesive application. By utilizing the natural tendency of CNTs to align under shear flow or magnetic field during processing, the system achieves axial alignment without requiring extremely precise positioning, thus managing manufacturing complexity while achieving the desired thermal conductivity enhancement.

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The use of CNTs in the adhesive layer significantly improves thermal conductivity, forming a parallel heat conduction path that enhances heat transfer from the face-sheet to the heat-pipe, thereby improving the efficiency of heat dissipation from the electronics package to outer space.

Implementation Method 1

a plurality of carbon nanotubes ('CNTs') within the adhesive layer... oriented in an axial direction between the face-sheet and the heat-pipe... act as a thermal bridge to enhance heat conduction from the face-sheet to the heat-pipe

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

at the hot interface 112 of the heat-pipe 108 a fluid (such as a liquid) in contact with the thermally conductive solid surface of the hot interface 112 turns into a vapor by absorbing heat from that surface of the hot interface 112. The vapor then travels along the heat-pipe 108 to a cold interface (not shown) and condenses back into a liquid

Methodology Applied
Scientific EffectPhase transition: Phase Change

Implementation Method 3

The vapor then travels along the heat-pipe 108 to a cold interface (not shown) and condenses back into a liquid - releasing the latent heat in the process

Methodology Applied
Scientific EffectLatent heat: Latent Heat

Data Source

PatentEP3073524B1High thermal conductivity joint utilizing continuous aligned carbon nanotubes
Publication Date: 2020.11.04 THE BOEING CO
  • EP3073524B1 patent drawingFigure 1
  • EP3073524B1 patent drawingFigure 2
  • EP3073524B1 patent drawingFigure 3

AI summary

Disclosed is a thermal conductive joint between a face-sheet and a heat-pipe on a radiator panel. The thermal conductive joint includes an adhesive layer attached between the face-sheet and the heat-pipe and a plurality of carbon nanotubes ("CNTs") within the adhesive layer.