Porous Heat Pipe Capillary Structure for Gravity-Resistant Fluid Return
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Solution Overview
Problem
Conventional heat pipes face limitations in shape complexity, material range, and dimensionality due to sintering and extrusion techniques, which restrict the effectiveness of capillary action, especially when operating under gravity.
Innovation Solution
A capillary device with a body portion containing porous chambers made from unmelted powdered material, allowing selective melting to create complex shapes and tailored porosity for enhanced capillary action, minimizing thermal conduction and parasitic heating, and enabling wider material usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If sintering technique is used to manufacture capillary structure, then capillary action is enabled for working fluid flow, but the range of materials and shape complexity is limited
Solution Approach 1:
The patent changes the manufacturing process from sintering to selective laser melting, altering the physical and chemical parameters of material processing. This enables the use of a broader range of materials including metals, ceramics, and polymers, while achieving complex three-dimensional geometries that were previously impossible with conventional sintering techniques.
Solution Approach 2:
The patent utilizes composite material structures combining different materials with complementary properties. The capillary channels can be formed from materials with high thermal conductivity while the surrounding structure uses materials optimized for mechanical strength or thermal insulation, achieving superior overall performance.
2Reliability
If extrusion technique is used to create axial grooves, then capillary structure is formed, but channel width is limited to 0.1-1mm which is too large for sufficient surface tension
Solution Approach 1:
The patent replaces the mechanical extrusion process with selective laser melting technology. This substitution enables the creation of capillary channels with widths in the micrometer range (10-100 times smaller than extrusion), generating sufficient surface tension to overcome gravity and enable reliable capillary action for working fluid transport.
Solution Approach 2:
The patent fundamentally changes the dimensional parameters of the capillary channels from millimeter-scale (0.1-1mm) to micrometer-scale (10-100 μm). This parameter change increases the surface area to volume ratio and enhances surface tension effects, making capillary action effective even against gravitational forces.
3Productivity
If conventional capillary structures are used, then working fluid can be transported, but thermal conduction into the structure causes parasitic heating of the fluid
Solution Approach 1:
The patent applies local quality differentiation by creating a porous capillary structure with controlled pore size distribution. The structure provides high surface area for capillary action while incorporating thermal insulation features in specific regions to minimize parasitic heat conduction to the working fluid, thus improving transport efficiency without unwanted heating.
Solution Approach 2:
The patent utilizes porous materials with optimized pore structures to enhance capillary action while controlling thermal conductivity. The porous structure provides numerous capillary channels for efficient fluid transport while the material composition and pore geometry are selected to minimize thermal conduction, reducing parasitic heating of the working fluid.
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 solution enhances fluid transfer and cooling performance by maximizing capillary action, allowing the device to operate effectively under gravity and supporting a wider range of dimensions and properties, while reducing weight and parasitic heating.
Implementation Method 1
at least part of the periphery of at least one said chamber is porous to allow flow of condensed working fluid through said unmelted powdered material in said chamber by means of capillary action
Implementation Method 2
forming successive layers of said body portion by means of selective melting of powdered material by means of an energetic beam
Data Source
AI summary
A capillary device (102) for use in a heat pipe in which heat is transferred from at least one evaporation region to at least one condensation region by means of evaporated working fluid is disclosed. The capillary device comprises a body portion defining chambers (108) containing powdered material (110) therein, wherein at least part of the periphery of at least one said chamber is porous to allow flow of condensed working fluid, by means of capillary action, through said powdered material in said chamber when flowing from a condensation region to an evaporation region.