Heat Pipe Wick Structure Axial Form Control

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Solution Overview

Problem

Conventional heat pipes struggle to meet the increasing heat dissipation requirements of advanced electronic devices due to limitations in the design and manufacturing of the wick core structure, which affects porosity, permeability, and capillarity, leading to reduced performance and yield.

Innovation Solution

The heat pipe design features a wick structure formed outside the pipe, allowing for customizable form and porosity/permeability control, eliminating the need for a core rod and enabling more efficient heat transfer by varying the wick structure's form along the axial and radial directions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a core rod is used to fix metal powder and form the wick core structure through high sintering, then the wick structure can be formed, but the core rod may be damaged during sintering or removal, and the wick structure will be damaged, reducing heat pipe performance

Engineering Contradiction:

Improveheat pipe performanceVSAvoidmanufacturing process complexity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The invention removes the core rod from the wick core structure formation process. The metal powder is directly formed into the wick structure without requiring a core rod to hold it together during sintering. This eliminates the damage risk to the core rod and the subsequent removal process, thereby improving heat pipe performance while simplifying manufacturing.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of using a core rod to hold metal powder and then removing it, the invention inverts the approach by allowing the metal powder to self-form the wick structure directly against the inner wall of the metal pipe during sintering. This inversion eliminates the need for the core rod entirely, resolving the contradiction between structural integrity during manufacturing and process simplicity.

Inventive Principle:

Principle #13The other way round (Inversion)

2Manufacturing precision

If the thickness of the sintering layer and powder diameter are determined by conventional methods, then the manufacturing process is simple, but the porosity and permeability cannot be accurately controlled, making it hard to control the yield of the wick core structure

Engineering Contradiction:

Improvewick core structure yield controlVSAvoidmanufacturing process complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The invention changes the control parameters from traditional thickness and powder diameter specifications to direct control of porosity and permeability values. By specifying the porosity (e.g., 30-70%) and permeability (e.g., 0.1-10 darcys) as target parameters, the manufacturing process can accurately control the wick core structure's performance characteristics, enabling precise yield control while maintaining process feasibility.

Inventive Principle:

Principle #35Parameter changes

3Power

If the wick structure is formed by groove, mesh or fine fiber, then the manufacturing process is simplified, but the capillarity is far less than the sintered-type heat pipe, reducing heat transfer capability

Engineering Contradiction:

Improveheat transfer capabilityVSAvoidmanufacturing process simplicity

Core Design Contradiction:

PowerVSEase of manufacture

Solution Approach 1:

The invention employs a sintered metal powder structure to create the wick core, utilizing the inherent porosity and capillary action of sintered materials. The sintered structure provides superior capillarity compared to groove, mesh, or fine fiber alternatives, enabling enhanced heat transfer capability while maintaining manufacturing feasibility through the direct formation process described.

Inventive Principle:

Principle #31Porous materials

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 approach enhances the yield and heat transfer performance of the heat pipe by allowing for precise control of wick structure characteristics, improving capillarity and heat transfer efficiency, and reducing manufacturing costs and defects.

Implementation Method 1

the heat generated by the heat source can evaporate the fluid (liquid phase) in the pipe into the vapor (vapor phase)

Methodology Applied

Scientific EffectEvaporation: Evaporation

Implementation Method 2

The generated vapor is driven by the vapor pressure difference to flow to the condenser of the heat pipe and then condenses back to the liquid phase after releasing the latent heat

Methodology Applied

Scientific EffectCondensation: Condensation

Implementation Method 3

lastly is driven by the capillarity to go back to the evaporator through the wick core structure

Methodology Applied

Scientific EffectCapillary action: Capillary Action

Implementation Method 4

the heat pipe can transfer the heat to the outside rapidly

Methodology Applied

Scientific EffectHeat conduction: Conduction (thermal)

Data Source

PatentUS20250180300A1Heat pipe

Publication Date: 2025.06.05 DELTA ELECTRONICS INC(CN)

AI summary

A heat pipe comprises a flat tube and a wick structure. The flat tube includes a hollow chamber and has two opposite sealed ends along an axial direction. The wick structure is disposed in the hollow chamber and extended along the axial direction of the flat tube. The wick structure has a smooth form with continuous edge and without the sectional difference along the axial direction. The front section is near the front sealed end, the rear section is near the rear sealed end. The smooth form has a maximum length parallel to the width direction, respectively. The maximum lengths are gradually decreased along the axial direction.