CNT Layer Stack for Aircraft De-icing

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Solution Overview

Problem

Existing methods for de-icing and anti-icing aircraft wings, such as using bleeder air or electric heating mats, are inefficient, heavy, and difficult to control, and electrically heatable paint with carbon nanotubes fails to meet durability and inspectability requirements.

Innovation Solution

An electrically heatable layer stack comprising substrate layers and carbon nanotube layers configured for remote Joule heating, where the carbon nanotube layer conducts electric current to produce heating in the substrate layers, with electrodes for current application and a heat sensor for temperature control, integrated into the aircraft skin for efficient and controlled heating.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If bleeder air from engine is used for heating, then de-icing function is achieved, but energy efficiency decreases and engine performance is reduced

Engineering Contradiction:
Improvede-icing functionVSAvoidengine efficiency
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent extracts the heating function from the engine system by using a separate electric heating element integrated into the wing skin, eliminating the need to tap bleeder air from the engine. This allows the engine to operate at full efficiency while the heating system provides independent de-icing capability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the pneumatic heating system (bleeder air) with an electric heating system using carbon nanotubes. This substitution eliminates the dependency on engine air supply and enables precise electronic control of heating parameters.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If bleeder air piping and nozzles are installed inside wings, then heating function is provided, but aircraft weight increases

Engineering Contradiction:
Improveheating functionVSAvoidaircraft weight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The patent uses a thin film heating element made of carbon nanotubes integrated directly into the wing skin structure. This eliminates the need for heavy internal piping, nozzles, and insulation layers, significantly reducing the overall system weight while maintaining effective heating function.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The heating element is merged with the wing skin structure itself, creating an integrated system where the skin serves both structural and heating functions. This eliminates separate heating components and reduces total weight.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If heating is applied at inside of skin, then heating source is protected, but energy efficiency decreases due to heat loss through skin thickness

Engineering Contradiction:
Improveheating source protectionVSAvoidheat loss
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

Instead of heating from the inside of the skin and relying on heat conduction through the skin thickness, the patent inverts the approach by applying the heating element directly to the outside surface of the skin. This eliminates heat loss through the skin and directly heats the external surfaces where de-icing is needed.

Inventive Principle:
Principle #13The other way round (Inversion)

4Ease of operation

If electric heating mats are attached inside wing skin, then temperature control is improved, but weight increases and inspection becomes cumbersome

Engineering Contradiction:
Improvetemperature controlVSAvoidheating system weight
Core Design Contradiction:
Ease of operationVSWeight of moving object

Solution Approach 1:

The patent replaces bulky electric heating mats with a thin film carbon nanotube heating element that can be integrated into the wing skin. This maintains excellent temperature control capabilities while dramatically reducing weight and simplifying inspection, as the thin film can be visually inspected for defects.

Inventive Principle:
Principle #30Flexible shells and thin films

5Weight of moving object

If carbon nanotube paint is applied, then lightweight heating is achieved, but durability and inspectability requirements are not met

Engineering Contradiction:
Improveheating system weightVSAvoidwear and durability
Core Design Contradiction:
Weight of moving objectVSReliability

Solution Approach 1:

The patent uses a composite structure where carbon nanotubes are embedded in a polymer matrix or applied as a structured coating rather than simple paint. This provides the lightweight benefit of carbon nanotubes while achieving the durability, adhesion, and inspectability required for aircraft applications.

Inventive Principle:
Principle #40Composite materials

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 solution provides efficient, lightweight, and controlled heating directly on the aircraft skin, overcoming the inefficiencies and weight issues of previous methods while meeting durability and inspectability requirements, ensuring effective de-icing and anti-icing without the need for extensive internal installations.

Implementation Method 1

The substrate layers and the at least one CNT-layer are configured to produce heating of at least one of the substrate layers when an electric current is applied to the at least one CNT-layer

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

The remote Joule heating may be caused in the substrate layer. An amount of remote Joule heating in the substrate layer may exceed an amount of Joule heating in the CNT-layer

Methodology Applied
Scientific EffectRemote Joule heating: Joule Heating

Data Source

PatentEP3244692B1Electrically heatable layer stack
Publication Date: 2021.06.23 AIRBUS OPERATIONS GMBH
  • EP3244692B1 patent drawingFigure 1~2
  • EP3244692B1 patent drawingFigure 3~4
  • EP3244692B1 patent drawingFigure 5

AI summary

An electrically heatable layer stack is described. The electrically heatable layer stack comprises at least two substrate layers, and at least one carbon nanotubes-, CNT-, layer, which is arranged between the substrate layers and which is configured to conduct an electric current. The substrate layers and the at least one CNT-layer are configured to produce heating of at least one of the substrate layers when an electric current is applied to the at least one CNT-layer. Further described are a vehicle assembly group, an aircraft, a method and a system for manufacturing an electrically heatable layer stack.