Secondary Sintered Capillary Structure for Heat Pipes
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Solution Overview
Problem
Existing phase change heat transfer devices, such as heat pipes and vapor chambers, suffer from poor air permeability and inefficient return flow of the working fluid due to capillary structures made of densely sintered metal powder, leading to difficulties in creating a sufficient pressure difference for smooth fluid flow and potential drying out of the working fluid at the heat source.
Innovation Solution
A phase change heat transfer device with a capillary structure made by secondary sintering, featuring sintered balls with first pores and larger second pores between them, which improves permeability and breathability, allowing for better fluid flow and retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metal powder is directly sintered to form a capillary structure with densely distributed pores, then the capillary structure can be formed, but the permeability is poor and air permeability is insufficient
Solution Approach 1:
The capillary structure is segmented into multiple layers with different pore characteristics. The lower portion (near heat source) has smaller pores for strong capillary action and fluid retention, while the upper portion has larger pores for better permeability and air flow. This segmentation resolves the contradiction by providing both capillary retention and permeability in different regions.
Solution Approach 2:
Different regions of the capillary structure are given different local qualities - the lower portion has smaller pore sizes optimized for fluid adsorption and retention, while the upper portion has larger pore sizes optimized for permeability and air flow. This local differentiation allows each region to perform its specific function optimally.
2Reliability
If pores are densely distributed in the capillary structure, then capillary action can be enhanced, but pressure difference sufficient to drive fluid flow cannot be provided
Solution Approach 1:
The capillary structure is divided into two functional zones: a lower zone with smaller pores that generate strong capillary pressure for fluid retention, and an upper zone with larger pores that provide pressure relief and facilitate fluid flow. This segmentation allows both strong capillary action and sufficient pressure difference to coexist.
Solution Approach 2:
The pore size parameter is changed across the height of the capillary structure. Smaller pore sizes in the lower portion provide higher capillary pressure, while larger pore sizes in the upper portion reduce flow resistance and maintain pressure difference for smooth fluid flow.
3Quantity of substance
If metal powder is sintered with small pores, then fluid retention is improved, but fluid flow smoothness is hindered
Solution Approach 1:
The capillary structure is segmented vertically with smaller pores in the lower portion for fluid retention and larger pores in the upper portion for smooth fluid flow. This segmentation allows the system to simultaneously achieve both fluid retention and smooth flow characteristics.
Solution Approach 2:
Different local pore qualities are assigned to different heights - smaller pores near the heat source for strong fluid adsorption and retention, and larger pores in the upper regions for reduced flow resistance and smooth fluid return flow.
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 secondary sintering process enhances the capillary structure's permeability and breathability, facilitating a more efficient return flow of the working fluid and preventing drying out, thereby improving the overall performance of the heat transfer device.
Implementation Method 1
The sintered metal powder has pores for adsorbing the working fluid in liquid state so that the working fluid is allowed to flow back to the heat source
Implementation Method 2
heat is absorbed into the liquid working fluid located at this portion. The working fluid in liquid state at this portion is therefore vaporized
Implementation Method 3
The working fluid in gaseous state is condensed when moves away from the heat source, and the working fluid then flows back to the heat source
Data Source
AI summary
This disclosure is directed to a heat transfer device and a manufacturing method thereof. The method has steps of: providing a metal powder, firstly sintering the metal powder to form a plurality of sintered balls that each sintered ball has a plurality of first pores; provide a thermally conductive housing, the sintered balls are secondly sintered to form a capillary structure combined with the thermally conductive housing, wherein at least a part of an internal wall of the thermally conductive shell is cover with the sintered balls, a plurality of second pores are defined between the sintered balls, and each first pore is smaller than each second pore; filling a working fluid into the thermally conductive housing; and sealing the thermally conductive housing to define a sealed chamber in the thermally conductive housing, so that the capillary structure and the working fluid are contained in the sealed chamber.