Multilayer CNT and PTC Heater Structure for Aircraft Wing De-icing
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Solution Overview
Problem
Carbon nanotube heaters for aircraft wings experience excessive power output and overheating at high temperatures due to negative temperature coefficient, and existing temperature sensor systems struggle to monitor and control temperature variations across the wing surface, leading to inefficiencies and potential system failure.
Innovation Solution
A multilayer structure comprising a first carbon nanotube heater layer with a negative temperature coefficient and a second positive temperature coefficient heater layer in electrical series, where the second layer compensates for excessive power by increasing resistance, creating a self-regulating thermal output to maintain a homogeneous temperature profile.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If carbon nanotube heaters are used for aircraft wing de-icing, then high power density and strength-to-weight ratio are achieved, but excessive power output and overheating occur at high temperatures due to negative temperature coefficient
Solution Approach 1:
The heater system is divided into two separate layers: a first heater layer with negative temperature coefficient (CNT heater) and a second heater layer with positive temperature coefficient (PTC heater). This segmentation allows each layer to perform different functions - the first layer provides high power density heating while the second layer provides temperature regulation, resolving the contradiction between high power output and temperature control stability.
Solution Approach 2:
The patent utilizes the temperature coefficient resistance parameter changes of different materials. The first heater layer has negative temperature coefficient (resistance decreases with temperature) while the second heater layer has positive temperature coefficient (resistance increases with temperature). By combining these opposite parameter responses, the system achieves self-regulating temperature control while maintaining high power density.
2Measurement precision
If multiple temperature sensors are installed to monitor wing surface temperature, then temperature monitoring capability is improved, but system complexity and installation difficulty increase
Solution Approach 1:
The PTC heater layer provides self-regulating temperature control through its inherent positive temperature coefficient property. As the temperature increases, the resistance automatically increases, reducing the current and preventing overheating. This self-service mechanism eliminates the need for complex sensor networks and control systems, while still achieving precise temperature monitoring and control.
Solution Approach 2:
The multilayer heater structure serves multiple functions simultaneously: the CNT heater layer provides heating, the PTC heater layer provides temperature regulation, and together they create a self-regulating system that monitors and controls temperature distribution across the wing surface without requiring external sensor networks.
3Measurement precision
If temperature sensors are installed across entire wing surface, then temperature distribution monitoring is improved, but installation impracticality increases
Solution Approach 1:
The patent merges the temperature monitoring and heating functions into a single integrated multilayer structure. The PTC heater layer not only heats but also inherently monitors and regulates temperature distribution across the entire wing surface through its resistance-temperature relationship, eliminating the need for separate sensor installations.
Solution Approach 2:
The PTC heater layer automatically monitors and regulates temperature distribution across the wing surface through its inherent positive temperature coefficient property, providing comprehensive temperature monitoring without requiring external sensor installations or complex control systems.
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 multilayer structure effectively stabilizes temperature and power output across the wing surface, preventing overheating and improving efficiency by balancing thermal dissipation and electrical current, thus ensuring a strong and lightweight heating solution for aircraft.
Implementation Method 1
the electro-thermal resistance of the carbon nanotube heaters decreases significantly (negative temperature coefficient), resulting in excessive power output
Implementation Method 2
the second heater layer has a positive temperature coefficient with respect to electrical resistivity
Implementation Method 3
maintain a homogeneous temperature profile
Implementation Method 4
stabilizes temperature and power output across the wing surface
Data Source
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AI summary
Disclosed is a multilayer structure, comprising: a first heater layer (16) comprising a CNT heater, wherein the CNT heater comprises a composite of carbon nanotubes and silicone; and a second heater layer (18) comprising a PTC heater, wherein the PTC heater comprises a composite of carbon black and polymer; wherein the first heater layer and the second heater layer are first and second respectively in an electrical series; wherein the first heater layer has a negative temperature coefficient with respect to electrical resistivity; and wherein the second heater layer has a positive temperature coefficient with respect to electrical resistivity. Also disclosed is an aircraft component comprising the multilayer structure.