Single and multi-layer mesh structures for enhanced thermal transport
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Solution Overview
Problem
Current thermal management technologies face challenges in enhancing phase-change heat transfer processes, particularly in condensation and boiling, due to limitations in surface refreshing, droplet growth, and thermal resistance, which hinder efficient heat dissipation in high-power electronics and industrial applications.
Innovation Solution
The development of single and multi-layer mesh structures with nanostructured features and interconnected microchannels that promote sucking flow condensation and capillary liquid film boiling, enhancing nucleation sites and liquid wicking to improve heat transfer coefficients and critical heat flux.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional condensation surfaces are used, then surface refreshing occurs through droplet roll-off, but heat transfer efficiency is limited by slow droplet growth and surface coverage
Solution Approach 1:
The patent employs a porous Teflon AF coating with controlled pore sizes (1-10 micrometers) that enables rapid vapor penetration and condensation. The porous structure provides numerous nucleation sites for droplet formation and facilitates quick droplet growth by allowing vapor to access multiple condensation locations simultaneously, thereby resolving the contradiction between heat transfer efficiency and droplet growth rate.
Solution Approach 2:
The invention creates localized hydrophobic regions within the porous Teflon AF coating that specifically promote droplet nucleation and growth. By engineering specific local properties (hydrophobicity, pore size distribution) within the coating, the system accelerates droplet formation and growth rates while maintaining overall heat transfer efficiency, addressing the contradiction between these two parameters.
2Productivity
If wicking structures with high porosity are used to increase evaporation area, then heat dissipation rate improves, but thermal resistance increases due to thick wicking structures
Solution Approach 1:
The patent optimizes the pore size parameter of the Teflon AF coating to fall within a specific range (1-10 micrometers). This parameter change enables the coating to provide sufficient evaporation area through its porous structure while maintaining thin film geometry that minimizes thermal resistance. The controlled pore size allows rapid liquid transport and vapor generation without requiring thick wicking structures, thus resolving the contradiction between heat dissipation rate and thermal resistance.
Solution Approach 2:
The invention utilizes a thin film porous Teflon AF coating rather than thick wicking structures. This thin film approach provides large specific surface area for evaporation while minimizing conduction resistance through the wicking layer itself. The thin film geometry, combined with the porous structure, enables high heat dissipation rates without the thermal resistance penalty associated with thick wicking materials.
3Productivity
If hydrophobic coatings are applied to enhance dropwise condensation, then surface refreshing improves, but droplet growth is inhibited due to water repellency
Solution Approach 1:
The porous Teflon AF coating with its specific pore size range (1-10 micrometers) creates a unique dual-function surface. The pores allow rapid vapor penetration and condensation (enhancing surface refreshing) while also providing capillary forces that retain growing droplets on the surface (extending droplet residence time). This resolves the contradiction by using pore-scale engineering to simultaneously achieve fast surface refreshing and adequate droplet growth.
Solution Approach 2:
The invention creates a composite surface structure combining Teflon AF polymer matrix with controlled pore architecture. This composite material exhibits both hydrophobic characteristics (from Teflon AF) for surface refreshing and capillary retention (from pore structure) for droplet growth. The composite nature allows the material to perform both functions simultaneously, resolving the contradiction between surface refreshing rate and droplet residence time.
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
These mesh structures significantly enhance condensation and boiling heat transfer efficiency by increasing droplet growth rates, reducing thermal resistance, and delaying surface dry-out, achieving higher heat flux and transfer coefficients compared to traditional methods.
Implementation Method 1
enhancing phase-change heat transfer processes, particularly in condensation and boiling
Implementation Method 2
promote sucking flow condensation
Implementation Method 3
enhancing phase-change heat transfer processes, particularly in condensation and boiling
Implementation Method 4
promote sucking flow condensation and capillary liquid film boiling
Implementation Method 5
enhancing nucleation sites and liquid wicking to improve heat transfer coefficients
Implementation Method 6
enhancing nucleation sites and liquid wicking to improve heat transfer coefficients
Data Source
AI summary
This disclosure describes single and multi-layer woven meshes designed to enable sucking flow condensation and capillary-driven liquid film boiling, respectively, for instance, in use in heat spreaders. The single-layer woven meshes can include a nanostructure coating and a hydrophobic coating, while the multi-layer meshes can include a microcavity coating and optionally a hydrophilic coating.