Additively Manufactured Oscillating Heat Pipe Channels for Stable Flow

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Solution Overview

Problem

Existing oscillating heat pipes face instabilities due to traditionally manufactured channels that cause intermittent evaporation and condensation of the working fluid, limiting their effectiveness in thermal energy transfer.

Innovation Solution

The use of additive manufacturing to create heat pipes with complex geometries and flow directing features, such as channels with various cross-sectional shapes and embedded flow directing features, enhances fluid flow and two-phase heat transfer, allowing for more efficient thermal energy transfer over large distances with low thermal resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If traditional manufacturing methods are used to create heat pipe channels, then manufacturing simplicity is maintained, but channel geometry complexity and flow stability are limited

Engineering Contradiction:
Improvechannel geometryVSAvoidmanufacturing complexity
Core Design Contradiction:
ShapeVSEase of manufacture

Solution Approach 1:

The patent applies parameter changes by transitioning from traditional manufacturing methods to additive manufacturing, enabling continuous variation in channel cross-sectional shapes, sizes, and configurations. This allows optimization of fluid flow characteristics and heat transfer efficiency while maintaining manufacturing feasibility through modern additive processes.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces dimensional complexity by creating channels with varying cross-sectional geometries along their length, including non-circular shapes and three-dimensional configurations. This multi-dimensional approach to channel design enables improved flow distribution and heat transfer performance that cannot be achieved with simple two-dimensional cross-sections.

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

2Reliability

If traditional manufacturing methods are used, then manufacturing process simplicity is maintained, but thermal energy transfer efficiency and stability deteriorate

Engineering Contradiction:
Improvethermal transfer stabilityVSAvoidmanufacturing process complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent utilizes parameter changes in channel geometry, including varying cross-sectional areas, shapes, and orientations along the channel length, to optimize two-phase flow stability and heat transfer efficiency. These geometric parameters are specifically designed to prevent flow instabilities and ensure reliable thermal energy transfer.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent incorporates dynamic flow directing features within the channels that adapt to flow conditions, enabling the system to maintain stable operation under varying thermal loads. These features include variable cross-sections and geometric variations that respond to changes in fluid flow and heat transfer requirements.

Inventive Principle:
Principle #15Dynamics

3Productivity

If complex channel geometries are implemented, then fluid flow and heat transfer are enhanced, but manufacturing difficulty increases

Engineering Contradiction:
Improveheat transfer efficiencyVSAvoidmanufacturing difficulty
Core Design Contradiction:
ProductivityVSEase of manufacture

Solution Approach 1:

The patent achieves enhanced heat transfer efficiency through three-dimensional channel configurations and varying cross-sectional geometries that optimize fluid flow distribution and thermal contact. These complex geometries are successfully manufactured using additive manufacturing processes that can create intricate three-dimensional structures in a single integrated process.

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

Solution Approach 2:

The patent optimizes heat transfer productivity by continuously varying channel parameters such as cross-sectional area, shape factors, and orientation angles along the channel length. These parameter variations are precisely controlled during additive manufacturing to maximize thermal energy transfer while maintaining manufacturing feasibility.

Inventive Principle:
Principle #35Parameter changes

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 additive manufacturing process enables the creation of heat pipes with improved thermal energy transfer efficiency and predictability, capable of handling small channel sizes and complex geometries not feasible with traditional methods, enhancing thermal energy transfer and stability.

Implementation Method 1

An inner surface of a channel includes a flow directing feature that is configured to promote a first direction of flow and that is configured to provide resistance against a second direction of flow that is opposite the first direction of flow

Methodology Applied
Scientific EffectFlow direction control:

Implementation Method 2

Heat pipes are passive, two-phase heat transfer devices that can effectively transfer large amounts of thermal energy over large distances

Methodology Applied
Scientific EffectTwo-phase heat transfer: Phase Change

Implementation Method 3

Existing heat pipes consist of channels filled with a two-phase mixture, which acts as the heat transfer medium or working fluid for the system

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 4

Existing heat pipes consist of channels filled with a two-phase mixture, which acts as the heat transfer medium or working fluid for the system

Methodology Applied
Scientific EffectCondensation: Condensation

Data Source

PatentEP3754281B1A method of fabricating an oscillating heat pipe
Publication Date: 2021.12.29 HAMILTON SUNDSTRAND CORP
  • EP3754281B1 patent drawingFigure 1A~1B
  • EP3754281B1 patent drawingFigure 2A~2G
  • EP3754281B1 patent drawingFigure 3A~3B

AI summary

A method of fabricating an oscillating heat pipe (10;110;210;310) includes building the oscillating heat pipe with a layer-by-layer additive manufacturing process such that the oscillating heat pipe includes a body (16;116) of solid material, an array (18;118) of channels (20;120), an evaporator portion (112), and a condenser portion (114). The array of channels are disposed in the body and define a continuous loop through which a fluid flows. The array of channels is formed by cavities in the body as the body is formed with layer-by-layer additive manufacturing. An inner surface of a channel includes a flow directing feature (30A;30B) that is configured to promote a first direction of flow and that is configured to provide resistance against a second direction of flow that is opposite the first direction of flow.