Composite Heat Pipe Wick Structure for Pressure-Driven Fluid Return
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Solution Overview
Problem
Traditional manufacturing processes are unable to produce heat pipes with composite wicks of varying porosity, which limits their ability to efficiently transport working fluids against pressure differentials in high-heat applications like nuclear reactors.
Innovation Solution
A method involving 3D additive manufacturing, specifically laser-directed energy deposition, is used to form a composite wick structure by creating a first impermeable wick and a second porous wick with finer porosity, where the first wick allows for long-distance fluid flow and the second wick enhances localized flow against greater pressure gradients, forming a monolithic structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional manufacturing processes are used, then production is simpler and more established, but composite wicks of varying porosity cannot be produced
Solution Approach 1:
The patent applies parameter changes by varying the porosity of different wick regions through controlled material deposition and processing parameters. The additive manufacturing process allows precise control of porosity parameters in different zones of the wick structure, enabling production of composite wicks with spatially varying porosity that traditional processes cannot achieve.
Solution Approach 2:
The patent employs composite materials by combining multiple wick materials with different porosity characteristics into a single integrated wick structure. This composite approach allows the heat pipe to utilize the advantages of different materials - some regions with higher porosity for long-distance transport and others with finer porosity for localized flow - resolving the contradiction between manufacturing capability and performance requirement.
2Productivity
If a single wick structure is used, then the design is simpler, but it cannot efficiently handle both long-distance and localized fluid flow requirements
Solution Approach 1:
The patent applies local quality by creating regions within the wick with different porosity characteristics optimized for specific functions. The distal region has porosity optimized for long-distance fluid transport while proximal regions have porosity optimized for localized flow and pressure gradient management. This spatial variation in local properties allows the single wick structure to perform multiple functions efficiently without requiring multiple separate components.
Solution Approach 2:
The patent segments the wick structure into distinct functional zones with different porosity characteristics. By dividing the wick into regions with varying porosity - from coarser distal regions to finer proximal regions - the design achieves both long-distance transport capability and localized flow control within a unified structure, balancing functionality with structural integration.
3Ease of operation
If coarser porosity is used throughout, then long-distance flow is facilitated, but localized flow against pressure gradients is insufficient
Solution Approach 1:
The patent applies local quality by assigning different porosity characteristics to different regions of the wick. The distal region employs coarser porosity to facilitate long-distance fluid flow with minimal resistance, while proximal regions utilize finer porosity to generate sufficient capillary pressure for localized flow against pressure gradients. This spatial differentiation in local quality ensures both flow facilitation and pressure differential handling are optimized in their respective zones.
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 enables improved thermal efficiency and effective heat transfer in nuclear reactor systems by creating a heat pipe with a composite wick structure that can handle pressure differentials more effectively than traditional designs.
Implementation Method 1
heating the mixture of the first material and the second material to a temperature (a) less than a melting temperature of the first material and (b) greater than a melting temperature of the second material to melt the second material
Implementation Method 2
melt the second material
Implementation Method 3
cooling the mixture of the first material and the second material to below the melting temperature of the second material such that the second material solidifies
Implementation Method 4
The condensed/cooled working fluid is then transported back to the evaporator region via capillary action
Data Source
AI summary
Heat pipes and methods of forming heat pipes, such as for use in nuclear reactor systems, are described herein. A representative method of forming a heat pipe includes forming a first wicking structure from a first material and forming a second wicking structure on the first wicking structure. Forming the second wicking structure can include mixing a second material and a third material, and heating the mixture of the second material and the third material to a temperature (a) less than a melting temperature of the second material and (b) greater than a melting temperature of the third material to melt the third material. The method can further include cooling the mixture of the second material and the third material to below the melting temperature of the third material such that the third material solidifies to bond together a plurality of particles of the second material into a porous structure.