Two-Phase Heat Transfer Device with Liquid Overflow Tank

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Solution Overview

Problem

Conventional two-phase heat transfer devices face challenges with surplus liquid disrupting operation and reducing the useful surface area for heat exchange, particularly due to the need for a liquid reservoir in thermal contact with the cold plate, which limits design flexibility and performance.

Innovation Solution

A two-phase heat transfer device with a closed cavity containing a two-phase fluid in liquid-vapor equilibrium, featuring a main capillary structure and an additional capillary medium for excess liquid storage, ensuring capillary continuity and avoiding thermal contact with the cold source, thus maintaining optimal fluid volume and preventing operational disruptions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If a liquid reservoir is placed in thermal contact with the cold plate to store excess liquid, then the liquid storage function is achieved, but the useful surface area for heat exchange is reduced and design constraints increase

Engineering Contradiction:
Improveliquid storage capacityVSAvoiduseful surface area for heat exchange
Core Design Contradiction:
Quantity of substanceVSArea of stationary object

Solution Approach 1:

The liquid reservoir is extracted from the cold plate structure and placed in the vapor phase circulation channel instead. This separation allows the reservoir to store excess liquid without occupying thermal contact surface area, thus resolving the contradiction between liquid storage capacity and heat exchange surface area.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The liquid reservoir is positioned in the vapor phase dimension rather than the liquid phase thermal contact dimension. By utilizing the vapor circulation channel space, the reservoir achieves liquid storage functionality without interfering with the cold plate's heat exchange surface, effectively adding a spatial dimension to the solution.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Quantity of substance

If a liquid reservoir is integrated into the heat pipe structure, then liquid storage is enabled, but device complexity and design constraints increase

Engineering Contradiction:
Improveexcess liquid storageVSAvoiddesign constraints
Core Design Contradiction:
Quantity of substanceVSDevice complexity

Solution Approach 1:

The vapor circulation channel serves dual functions: it allows vapor phase heat transfer and simultaneously accommodates the liquid reservoir for excess liquid storage. This multi-functionality reduces the need for separate dedicated reservoir structures, thereby simplifying the overall device design while maintaining liquid storage capability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The liquid reservoir is merged with the vapor circulation channel structure rather than being a separate component. This integration eliminates additional connections and interfaces, reducing design complexity while enabling excess liquid storage functionality within the existing heat pipe architecture.

Inventive Principle:
Principle #5Merging (Combining)

3Quantity of substance

If excess liquid accumulates in the heat transfer device, then liquid volume increases, but operational reliability is disrupted

Engineering Contradiction:
Improveliquid volumeVSAvoidoperational reliability
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The liquid reservoir is pre-positioned in the vapor circulation channel to provide a designated storage location for excess liquid before it can cause operational disruptions. This preliminary arrangement ensures that when liquid volume increases during operation, the excess liquid has a predetermined destination, maintaining system reliability.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The excess liquid, which would normally be a harmful factor disrupting operation, is converted into a beneficial stored resource by directing it into the reservoir within the vapor channel. This transforms the potential harm of liquid accumulation into a useful feature of controlled liquid storage that maintains operational reliability.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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

This design enhances thermal performance by optimizing heat exchange and reducing design constraints, allowing for efficient heat transfer without surplus liquid interference, suitable for both space and Earth-based applications.

Implementation Method 1

at least one main capillary structure adapted to allow the circulation of the two-phase fluid in the liquid phase between said cold source and said hot source

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Implementation Method 2

at least one additional capillary medium allowing storage and restitution of an excess of liquid relative to a maximum capacity of liquid contained in the main capillary structure, said additional capillary medium and said main capillary structure being connected so as to ensure capillary continuity

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Implementation Method 3

a saturated two-phase fluid, one portion of which is in the liquid phase and another portion in the gas phase

Methodology Applied
Scientific EffectPhase change: Phase Change

Implementation Method 4

The heat transfer device is in a heat exchange relationship, on the one hand, with a so-called hot source, and on the other hand with a so-called cold source

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Data Source

PatentEP4323711B1Two-phase heat-transfer device with liquid overflow tank
Publication Date: 2024.08.07 AIRBUS DEFENCE & SPACE SAS
  • EP4323711B1 patent drawingFigure 1a~2
  • EP4323711B1 patent drawingFigure 3~4
  • EP4323711B1 patent drawingFigure 5~7

AI summary

Disclosed is a two-phase heat-transfer device, said device comprising a closed cavity comprising at least one evaporation zone (20) subjected to heat exchange with at least one heat source and at least one condensation zone (30) subjected to heat exchange with at least one cold source, the closed cavity containing a two-phase fluid with a liquid-steam balance and comprising at least one channel (13) for circulating the two-phase fluid in the steam phase and at least one main capillary structure (14) suitable for allowing the two-phase fluid to circulate in the liquid phase between the cold source and the heat source, the two-phase device being characterised in that it further comprises at least one additional capillary medium (15) for storing and restoring excess liquid relative to a maximum capacity of liquid contained in the main capillary structure, the additional capillary structure and the main capillary structure being connected to each other so as to ensure capillary continuity for the two-phase fluid in the liquid phase.