Microscale Canopy Wick Structure for Capillary-Permeability Decoupling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Traditional heat pipe wick structures face a challenge where capillary pressure and viscous resistance are coupled, leading to inhibited liquid transport as the size of the surface decreases, limiting their ability to maintain efficient heat transfer and cooling performance.
Innovation Solution
A microscale canopy wick structure is fabricated using a method that decouples capillary pressure and permeability by controlling the width of capillary pressure regions and fluid flow channels through selective etching processes, allowing for enhanced liquid flow and coverage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If the size of the wick surface is reduced to increase capillary pressure, then capillary pressure increases, but liquid transport is inhibited due to significant viscous resistance
Solution Approach 1:
The wick structure is divided into distinct functional regions: capillary pressure regions with narrow spacings (1-10 micrometers) for generating capillary pressure, and flow channels with wider spacings (10-100 micrometers) for liquid transport. This segmentation allows each region to optimize its function without compromising the other.
Solution Approach 2:
Different regions of the wick structure have different local properties: the capillary pressure regions have small spacings to generate high capillary pressure, while the flow channels have larger spacings to reduce viscous resistance. This local differentiation resolves the contradiction by allowing each zone to have the properties needed for its specific function.
2Reliability
If traditional heat pipe wick structures are used, then passive liquid transport is achieved, but heat transfer performance is limited due to coupled capillary pressure and viscous resistance
Solution Approach 1:
The invention transitions from a uniform one-dimensional wick structure to a two-dimensional structured array with distinct spatial zones. The capillary pressure regions and flow channels are arranged in a planar configuration, allowing simultaneous optimization of capillary pressure generation and liquid transport in different spatial locations.
3Productivity
If ultrathin membrane supported by wide flow channels is used to achieve good permeability, then liquid transport is improved, but fabrication becomes complicated and unsuitable for practical application
Solution Approach 1:
The wick structure uses a porous solid matrix material (such as sintered metal or ceramic) that naturally forms interconnected pores. This porous structure inherently provides both capillary pressure generation and liquid transport pathways, eliminating the need for complex supported membrane fabrication while achieving the desired dual functionality.
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 decoupling of capillary pressure and permeability in the microscale canopy wick structure enables improved heat transfer and cooling performance by allowing for greater fluid flow rates and surface coverage, preventing overheating and enhancing the overall efficiency of heat transfer devices.
Implementation Method 1
all traditional heat pipes rely on passive liquid transport by capillary action that is generated by a porous wick material
Implementation Method 2
controlling the width of a capillary pressure region between canopy members of adjacent wicks by selectively etching the substrate
Data Source
AI summary
One or more methods of fabricating a microscale canopy wick structure having an array of individual wicks having one or more canopy members. Each method includes selectively etching a substrate to control the thickness of the canopy members and also control the width of a fluid flow channel between adjacent wicks in a manner that enhances the overall performance of the microscale canopy wick structure.