Dual-Mode Passive Heat Sink Cell for Missile Electronics
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Solution Overview
Problem
Traditional thermal management systems for high-speed missiles are limited by temperature differentials during flight, which restrict heat transfer efficiency, and often require electrical power or cryogenic cooling, making them unsuitable for all operational conditions.
Innovation Solution
A dual-mode passive thermal management system utilizing a heat sink cell with a shape memory alloy (SMA) that automatically switches between endothermic and exothermic reactions to maintain thermal protection within operational limits of electronic circuitry without electrical energy, using a thermal conducting conduit for heat transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If traditional thermal management systems use heat exchangers and phase change materials, then cooling capability is improved, but system complexity and electrical power requirements increase
Solution Approach 1:
The system utilizes phase change materials that undergo phase transitions at specific temperature thresholds to provide passive thermal management. The PCM melts at a predetermined temperature to absorb excess heat from electronics, and the shape memory alloy activates at a higher temperature to trigger material mixing and initiate endothermic reactions, eliminating the need for complex active cooling systems and electrical power requirements
Solution Approach 2:
The thermal management system operates autonomously without external control or power supply. The phase change materials and shape memory alloy automatically respond to temperature changes, triggering phase transitions and material mixing based on thermal conditions alone, providing self-regulating thermal protection for electronic components
2Reliability
If active electric cooling systems are used, then thermal protection is improved, but electrical power consumption increases
Solution Approach 1:
The system employs phase change materials that automatically absorb heat during phase transitions (solid to liquid) at predetermined temperatures. This passive phase change mechanism provides reliable thermal protection without requiring electrical power, as the phase transition process inherently absorbs excess thermal energy from electronic components
Solution Approach 2:
The system converts the harmful effect of excessive heat into a beneficial cooling mechanism through endothermic chemical reactions. When the shape memory alloy activates due to high temperature, it triggers the mixing of materials that undergo endothermic reactions, effectively using the heat problem itself to drive the cooling process without additional power input
3Temperature
If cryogenic cooling systems are used, then initial cooling performance is improved, but system complexity and operational constraints increase
Solution Approach 1:
The phase change materials are pre-positioned within the thermal management system during manufacturing, ready to activate at specific temperature thresholds. This preliminary preparation allows the system to immediately respond to thermal loads without requiring external intervention or complex operational procedures, enhancing both performance and operational flexibility
Solution Approach 2:
The system transitions from static thermal management to dynamic response through the use of shape memory alloys that change shape or activate at specific temperatures. This dynamic behavior allows the system to adapt to varying thermal conditions during operation, providing versatile thermal protection across different flight conditions without operational constraints
4Productivity
If heat transfer efficiency is increased through active systems, then thermal management performance is improved, but device complexity increases
Solution Approach 1:
The system replaces complex mechanical active cooling systems with passive thermal management based on phase change materials and shape memory alloys. These materials automatically respond to temperature changes through phase transitions and shape changes, achieving effective heat transfer without mechanical components, motors, 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
Provides on-demand cooling or heating to maintain electronic circuitry within safe temperature ranges, ensuring fail-safe thermal protection across varying flight conditions without electrical power, enhancing heat transfer efficiency and operational reliability.
Implementation Method 1
A shape memory alloy (SMA) is coupled to and closes the opening of the second reservoir. The SMA is responsive to a temperature change of the first material, or responsive to temperature change(s) external to the first material, to automatically open the opening
Implementation Method 2
the first material or the second material spontaneously pass through the opening to cause an endothermic or exothermic reaction between the first material and the second material
Implementation Method 3
the first material or the second material spontaneously pass through the opening to cause an endothermic or exothermic reaction between the first material and the second material
Implementation Method 4
a thermal conducting conduit (TCC) for the transfer of heat between the external object and the heat sink cell
Implementation Method 5
Traditional thermal management approaches for high-speed missile applications involve heat exchangers and/or phase change materials to cool critical missile electronics
Data Source
AI summary
Embodiments include a heat sink cell comprising a first reservoir having a first volume of space and a first material stored in the first volume of space. The first material provides a first heat sink thermal operating range for the transfer of heat. The cell comprises a second reservoir and a second material stored in the second reservoir. A shape memory alloy (SMA) closes an opening of the second reservoir. The SMA is responsive to a temperature change of the first material or external sources to automatically open the opening so that the first material or the second material spontaneously pass through the opening to cause an endothermic reaction or an exothermic reaction between the first material and the second material to create a second heat sink thermal operating range different from the first heat sink thermal operating range. Embodiments also include a system and method of dual-mode passive thermal management.