Flexible Bladder Thermal Control for Phase-Change Expansion
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Solution Overview
Problem
Current thermal control systems for space exploration and earth-based thermally demanding environments face challenges in efficiently managing thermal loads during atmospheric re-entry and maintaining temperature stability for payloads and EVA suits, particularly with the use of water-based phase-change materials that expand volumetrically during phase transitions.
Innovation Solution
A portable thermal control system utilizing a Phase Change Material (PCM) cooled to below its isothermic phase-change temperature, integrated within an atmospheric-entry vehicle and EVA suits, which absorbs atmospheric entry heat through both sensible and latent heat processes, using a water-based PCM and a compressible insert to manage volume expansion and maintain thermal interaction with heat-exchanging walls.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If water-based phase-change material is used for thermal control, then thermal control efficiency is improved through latent heat absorption, but volume expansion during phase transition causes container rupture
Solution Approach 1:
The patent employs a flexible bladder made of elastomeric material to contain the water-based phase-change material. This flexible membrane allows the PCM to expand volumetrically during freezing while preventing rupture of the rigid container. The bladder expands to accommodate the volume increase and then contracts during melting, enabling repeated thermal cycles without structural damage.
2Stability of the object's composition
If rigid container is used to hold phase-change material, then structural stability is improved, but volume expansion during freezing causes container rupture
Solution Approach 1:
The patent introduces a flexible elastomeric bladder as an intermediate containment structure between the rigid container and the phase-change material. This flexible intermediate layer absorbs the volumetric expansion stress during freezing while the rigid outer container maintains overall structural stability and provides mechanical support.
3Use of energy by moving object
If phase-change material is allowed to expand freely, then thermal control performance is improved, but mechanical disruption of crystalline structure reduces heat transfer efficiency
Solution Approach 1:
The flexible elastomeric bladder contains the phase-change material while allowing controlled expansion. The elasticity and flexibility of the bladder material provide gentle mechanical constraints that guide crystallization without causing disruptive stress, thereby maintaining both thermal control performance and heat transfer efficiency.
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
Effectively prevents overheating of payloads during atmospheric re-entry and provides efficient thermal management for EVA suits by utilizing latent and sensible heat storage, ensuring temperature stability and preventing container rupture due to volume expansion of the PCM.
Implementation Method 1
wherein such latent-heat processes are structured and arranged to be effected by phase transition of such at least one phase-change material from solid-state to liquid-state
Implementation Method 2
wherein such sensible-heat processes are effected by transition of such at least one phase-change material from at least one sub-phase-change temperature (below 0° C. for water-based materials) to a higher temperature
Implementation Method 3
control the expansion of a water-based PCM during phase transition of the PCM between a liquid state and solid state
Data Source
AI summary
A portable thermal-control system adapted to support space-related research and exploration. Embodiments of the present invention assist in preventing overheating of small payloads being transported from an orbiting space vehicle to a planetary surface by small atmospheric-entry vehicles. Other embodiments of the present invention provide thermal control within an extra-vehicular activity (EVA) suit. Each embodiment utilizes at least one phase-change material, cooled significantly below the freezing temperature, to absorb heat.