Variable-Thickness Composite Wick Heat Pipe for Continuous Liquid Return

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Solution Overview

Problem

Conventional heat pipes exhibit inefficient cooling cycles due to inadequate capillary structure design, leading to suboptimal heat dissipation efficacy in electronic devices and machinery.

Innovation Solution

A heat pipe with a composite capillary structure featuring a first capillary structure with variable thickness and a second capillary structure, where the first capillary structure has a grooved shape and is integrated with the pipe body, and the second capillary structure is disposed on the first structure, providing a gradual thickness increase from the evaporation section towards the condensation section, enhancing capillary force and permeability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a conventional uniform capillary structure is used in heat pipes, then the structure is simple and easy to manufacture, but the cooling cycle efficiency is insufficient and heat dissipation performance is suboptimal

Engineering Contradiction:
Improveheat dissipation efficiencyVSAvoidcapillary structure complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The capillary structure is designed with variable thickness along the length of the heat pipe, with different sections having different capillary characteristics. The evaporation section has a specific capillary thickness optimized for liquid return, while other sections have different thicknesses optimized for their respective functions, allowing each local region to perform its function efficiently

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The heat pipe is divided into multiple sections (evaporation section, condensation section, adiabatic section) with distinct capillary structure characteristics in each section. This segmentation allows optimization of the capillary structure for specific functions in specific regions, improving overall heat dissipation efficiency

Inventive Principle:
Principle #1Segmentation

2Reliability

If the capillary structure thickness is increased to enhance capillary force, then liquid return capability is improved, but thermal resistance increases and heat dissipation performance deteriorates

Engineering Contradiction:
Improveliquid return capabilityVSAvoidthermal resistance
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The capillary structure has different thicknesses in different sections: the evaporation section has a larger capillary thickness to provide strong capillary force for reliable liquid return, while other sections have optimized thicknesses that balance capillary force and thermal conductivity, minimizing thermal resistance while ensuring adequate liquid return capability

Inventive Principle:
Principle #3Local quality

3Productivity

If a single-layer capillary structure is used, then the manufacturing process is simple, but the cooling cycle efficiency remains insufficient

Engineering Contradiction:
Improvecooling cycle efficiencyVSAvoidcapillary structure layers
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The heat pipe structure nests different functional sections within a single integrated body, with each section having optimized capillary characteristics. The evaporation section is nested within the overall heat pipe structure with specific capillary thickness, allowing efficient cooling cycle operation without requiring multiple separate components or layers

Inventive Principle:
Principle #7Nested doll (Nesting)

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 variable thickness design improves heat dissipation efficiency by ensuring continuous fluid flow and reducing thermal resistance, thereby preventing dry burning and enhancing cooling performance.

Implementation Method 1

after the liquid cooling fluid in the heat pipe absorbs heat at the evaporation end

Methodology Applied
Scientific EffectHeat conduction: Conduction (thermal)

Implementation Method 2

the liquid cooling fluid vaporizes and moves to the condensation end by vapor pressure

Methodology Applied
Scientific EffectEvaporation: Evaporation

Implementation Method 3

After the gaseous cooling fluid at the condensation end is exothermic and condensed into liquid cooling fluid

Methodology Applied
Scientific EffectHeat conduction: Conduction (thermal)

Implementation Method 4

the gaseous cooling fluid at the condensation end is exothermic and condensed into liquid cooling fluid

Methodology Applied
Scientific EffectCondensation: Condensation

Implementation Method 5

the liquid cooling fluid flows back to the evaporation end through capillary structures inside the heat pipe

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Data Source

PatentEP4610586A1Heat pipe
Publication Date: 2025.09.03 PURPLE CLOUD DEV PTE LTD
  • EP4610586A1 patent drawingFigure 1
  • EP4610586A1 patent drawingFigure 2
  • EP4610586A1 patent drawingFigure 3

AI summary

A heat pipe includes a pipe body having an evaporation section, a condensation section, and a transmission section, the evaporation section and the condensation section are respectively connected to opposite ends of the transmission section, and a composite capillary structure including a first capillary structure and at least one second capillary structure, the first capillary structure having a grooved shape and being disposed on an inner surface of the pipe body, the second capillary structure being at least partially disposed on the first capillary structure, the first capillary structure and the at least one second capillary structure extending from the evaporation section to the condensation section, wherein the composite capillary structure has a variable thickness within the evaporation section.