Multi-layer mesh wicks with offset warp directions
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Solution Overview
Problem
Conventional heat pipe wick designs face challenges in achieving high thermal conductivity, capillary pumping pressure, and fluid permeability while being economically practical, often resulting in unstable structures that collapse due to peak-to-valley alignment of woven mesh layers.
Innovation Solution
The use of multi-layer woven mesh wicks with offset warp directions between layers, where the inter-layer warp offset angle is greater than 2.5 degrees and less than or equal to 87.5 degrees, enhances porosity and stability, reducing the likelihood of collapse and maintaining high thermal conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional low-cost wick technologies such as groove and mesh wicks are used, then manufacturing cost is reduced, but thermal conductivity cannot be achieved without significant reduction of fluid permeability or capillary pumping pressure
Solution Approach 1:
The patent uses composite materials by combining multiple mesh layers with different weave patterns (e.g., plain weave, twill weave, satin weave) to create a wick structure that achieves high thermal conductivity while maintaining fluid permeability and capillary pumping pressure. The composite structure allows each layer to contribute different properties, solving the contradiction between cost-effectiveness and thermal performance.
Solution Approach 2:
The patent applies local quality by varying the weave pattern and orientation of individual mesh layers within the composite structure. Different layers have different local properties (weave density, fiber orientation, porosity) that are optimized for specific functions: some layers provide thermal conduction pathways while others maintain fluid flow channels, resolving the contradiction between thermal conductivity and fluid permeability.
2Temperature
If multiple mesh layers are stacked to increase thermal conductivity, then thermal performance improves, but alignment issues cause instability and reduced performance
Solution Approach 1:
The patent applies asymmetry by using different weave patterns and orientations for adjacent mesh layers. Instead of stacking identical layers with aligned patterns, the invention uses asymmetric combinations (e.g., plain weave followed by twill weave at a specific angle) that prevent alignment issues and improve structural stability while maintaining thermal conductivity.
Solution Approach 2:
The patent resolves alignment issues by introducing angular orientation as an additional dimension of control. Mesh layers are stacked with specific angular offsets (e.g., 45 degrees, 60 degrees) between adjacent layers, transforming the problem from two-dimensional alignment to three-dimensional spatial arrangement, which enhances structural stability while preserving thermal pathways.
3Reliability
If additional materials are added to improve wick parameters, then performance may improve, but cost increases and thermal conductivity may be compromised
Solution Approach 1:
The patent uses porous materials by utilizing the inherent porosity of woven mesh structures. The weave patterns create controlled void spaces that provide fluid permeability and capillary action without requiring additional porous materials. This achieves high wick performance (fluid transport and thermal conduction) using only the mesh structure itself, avoiding the need for expensive additional 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 results in heat pipes with increased fluid permeability and resistance to collapse, while maintaining high thermal conductivity, thus improving heat transfer efficiency without significant economic or technological impracticalities.
Implementation Method 1
The condensed liquid is then returned to the evaporator, typically by capillary action within a wick structure within the heat pipe.
Implementation Method 2
The wick structure includes a first woven mesh layer and a second woven mesh layer disposed on the first woven mesh layer. In the heat pipe, the first woven mesh layer is a first weave pattern of thermally conductive fibers
Data Source
AI summary
Methods for fabricating heat pipes and heat pipes therefrom are provided. The heat pipe (400) includes a heat pipe body (402) having an inner cavity (408), and a wick structure (404) disposed in the inner cavity. The wick structure includes a first woven mesh layer (410) and a second woven mesh layer (412) disposed on the first woven mesh layer. In the heat pipe, the first woven mesh layer is a first weave pattern of thermally conductive fibers (103) having a first warp direction (W3 or W4) and the second woven mesh layer is a second weave pattern of thermally conductive fibers (105) having a second warp direction (W5 or W6). The second woven mesh layer is disposed on the first woven mesh layer such that the first and the second warp directions are rotationally offset by an inter-layer warp offset angle (γi).