Passive Thermal Management Using Shape Memory Alloys
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Solution Overview
Problem
Current thermal management systems for aerospace and cryogenic applications are heavy, costly, and prone to failure due to reliance on active controls and complex devices, which limits their ability to efficiently manage heat across broad area surfaces and extreme temperatures.
Innovation Solution
A passive thermal management system utilizing shape memory alloys (SMAs) that adjust heat conduction based on temperature changes, allowing for automatic switching between insulating and conductive states without mechanical or electrical stimuli, enabling efficient heat transfer across broad area surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If active controls, sensors, pneumatics, hydraulics, powered pumps, and heaters are used for thermal management, then temperature control capability is improved, but system mass increases
Solution Approach 1:
The shape memory alloy elements automatically respond to temperature changes and mechanically actuate thermal switches without requiring external control systems, sensors, or power sources. The SMA materials self-regulate the thermal conduction state based on ambient temperature, eliminating the need for active control components and thereby reducing system mass
Solution Approach 2:
The patent replaces complex mechanical control systems (pneumatics, hydraulics, powered pumps) with passive shape memory alloy elements that utilize thermal-mechanical coupling. The SMA elements directly convert temperature changes into mechanical displacement to control thermal switches, substituting complex mechanical systems with simpler thermomechanical materials
2Temperature
If active controls and complex devices are used for thermal management, then temperature regulation is improved, but system cost increases
Solution Approach 1:
The shape memory alloy elements automatically respond to temperature changes and mechanically actuate thermal switches without requiring external control systems, sensors, or power sources. The SMA materials self-regulate the thermal conduction state based on ambient temperature, eliminating the need for active control components and thereby reducing system mass
Solution Approach 2:
The patent employs shape memory alloy elements that can be integrated into the thermal management structure at low cost. These SMA components are simple passive elements that can be manufactured and replaced economically, replacing expensive active control devices with more affordable passive materials
3Temperature
If active controls and powered devices are used for thermal management, then thermal control precision is improved, but power consumption increases
Solution Approach 1:
The shape memory alloy elements automatically respond to temperature changes and mechanically actuate thermal switches without requiring external control systems, sensors, or power sources. The SMA materials self-regulate the thermal conduction state based on ambient temperature, eliminating the need for active control components and thereby reducing system mass
Solution Approach 2:
The patent replaces complex mechanical control systems (pneumatics, hydraulics, powered pumps) with passive shape memory alloy elements that utilize thermal-mechanical coupling. The SMA elements directly convert temperature changes into mechanical displacement to control thermal switches, substituting complex mechanical systems with simpler thermomechanical materials
4Temperature
If active controls and complex devices are used for thermal management, then temperature management capability is improved, but system reliability decreases
Solution Approach 1:
The shape memory alloy elements automatically respond to temperature changes and mechanically actuate thermal switches without requiring external control systems, sensors, or power sources. The SMA materials self-regulate the thermal conduction state based on ambient temperature, eliminating the need for active control components and thereby reducing system mass
Solution Approach 2:
The patent removes complex active control components, sensors, and powered devices from the thermal management system, retaining only the essential passive shape memory alloy elements. By extracting unnecessary complex components, the system achieves improved reliability through reduced failure modes while maintaining temperature management capability
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 system provides efficient, reliable, and self-regulating thermal management with reduced mass and power consumption, suitable for aerospace and cryogenic applications, and can be applied to various systems requiring on-demand heat transfer and temperature control.
Implementation Method 1
One or more passively-acting elements are attached to the inner surface of the first substrate and include a shape memory material. The shape memory material passively reacts to the temperature of the first substrate by thermally contacting or separating from the second inner surface of the second substrate for the control of the conduction of heat energy.
Data Source
AI summary
A thermal management system includes a first substrate having a first conductive inner surface. A second substrate has a second conductive inner surface. A connecting structure is attached to the first and second substrates to space apart the first and second inner surfaces defining an insulating space for a single architecture. One or more passively-acting elements are attached to the inner surface of at least one substrate and including a shape memory material such as a shape memory alloy (SMA). The SMA passively reacts to the temperature of the first substrate by thermally contacting or separating from the second inner surface of the second substrate for the control of the conduction of heat energy in either direction.