Flat Heat Pipe Gradient Wetting Structure Reduces Thermal Resistance
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Solution Overview
Problem
Existing flat heat pipes rely heavily on capillary force provided by wicks, leading to increased heat transfer resistance and energy consumption, with sintered wick structures being difficult to guarantee quality.
Innovation Solution
A flat heat pipe with a gradient wetting structure, featuring micron-level radial strips on the bottom plate and superhydrophilic/superhydrophobic radial structures on the top plate, combined with a wick on the support plate, to enhance reflux and condensate transport without pumps, reducing thermal resistance and improving heat transfer efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If wicks are used to promote reflux of working fluid, then reflux capability is improved, but heat transfer resistance increases
Solution Approach 1:
The invention applies different wetting properties to different regions of the heat pipe surface. The evaporation region has hydrophilic properties to facilitate liquid supply, while the condensation region has hydrophobic properties to promote condensate removal. This local differentiation eliminates the need for wicks in critical areas, reducing thermal resistance while maintaining reflux capability through surface tension gradients.
Solution Approach 2:
The invention replaces the mechanical wick structure with a surface tension-based liquid transport mechanism. By creating a wetting gradient through chemical or physical surface modification, the system uses interfacial tension forces instead of capillary forces from porous wicks, thereby reducing thermal resistance at the solid-liquid interface while maintaining effective liquid reflux.
2Ease of operation
If sintered wick structure is used, then liquid transport is improved, but manufacturing quality becomes difficult to guarantee
Solution Approach 1:
The invention replaces the sintered wick structure with a surface-modified solid plate. The liquid transport function is achieved through wetting gradient created by surface treatment (chemical etching, plasma treatment, or coating) rather than through capillary action in porous sintered material. This eliminates the complex sintering process and its associated quality control issues while maintaining effective liquid transport.
Solution Approach 2:
The invention changes the surface parameters (wetting properties) of the solid plate to create a gradient from hydrophilic to hydrophobic regions. This parameter change approach allows for simpler manufacturing processes compared to sintering, as surface treatment can be applied more consistently and controlled more precisely, thereby improving manufacturing quality while maintaining liquid transport functionality.
3Productivity
If wicks cover evaporating and condensing surfaces, then working fluid circulation is improved, but thermal resistance increases
Solution Approach 1:
The invention applies different surface properties to different functional regions: the evaporation region is made hydrophilic to enhance liquid supply to the phase change interface, while the condensation region is made hydrophobic to facilitate rapid condensate removal. This local differentiation eliminates the need for continuous wick coverage, reducing thermal resistance while maintaining effective fluid circulation through surface tension-driven flow.
Solution Approach 2:
The invention extracts the wick material from the evaporating and condensing surfaces, retaining only the essential liquid transport function through surface tension gradients. By removing the wick layer from critical heat transfer zones, the thermal resistance is reduced while the working fluid circulation is maintained through the wetting gradient mechanism.
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 gradient wetting structure accelerates the reflux of the working fluid and enhances heat transfer performance by reducing heat transfer resistance, improving the overall heat transfer capability of the flat heat pipe.
Implementation Method 1
A micron-level radial strip is processed on the inner surface of the bottom plate, presenting a wetting gradient that changes uniformly from the center to the circumference of a circle, which is used to transport liquid and collect condensate without a pump in the direction of the center of the circle
Implementation Method 2
The inner surface of the top plate is processed with superhydrophilic and superhydrophobic radial structures arranged at intervals to transport the condensate to the direction of the surrounding pipe wall
Implementation Method 3
A wick is arranged on the inner side of the support plate, to transfer the liquid from the edge of the top plate to the edge of the bottom plate
Implementation Method 4
Its working principle is similar to ordinary heat pipe, that is, removing the heat of electronic components by virtue of phase change latent heat of working fluid
Implementation Method 5
When the heat passes through the evaporation zone of the flat heat pipe from the heat source, the liquid working fluid boils and vaporizes in the low-vacuum airtight chamber
Implementation Method 6
the gas on the condensation surface condensates and releases heat
Data Source
AI summary
The present invention discloses a flat heat pipe, comprising a bottom plate, a top plate, and a support plate located between the bottom plate and the top plate; a micron-level radial strip is processed on the inner surface of the bottom plate; the inner surface of the top plate is processed with superhydrophilic and superhydrophobic radial structures arranged at intervals to transport the condensate to the direction of the surrounding pipe wall; a wick is arranged on the inner side of the support plate. The present invention has the function of pumpless directional transport of liquid and convergence of refluxed condensate; thereby improving the heat exchange performance of the entire flat heat pipe.