Micro-Channel Pulsating Heat Pipe With Obstructions for Stable Vaporization
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Solution Overview
Problem
Existing pulsating heat pipes (PHPs) face limitations in heat transfer capabilities and are not widely adopted for heat management in electronic devices, particularly in high-power density applications, due to insufficient vaporization and flow instability, which leads to overheating and performance issues.
Innovation Solution
Incorporating various geometries with regular or randomized obstructions within the pipes to facilitate nucleation, such as semispherical and hemicylindrical attachments, and using ribbing and plating to enhance surface area, thereby improving fluid flow and vaporization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional heat pipes or heatsinks are used, then the structure is simple and easy to manufacture, but the heat transfer capability is insufficient for high-power density applications
Solution Approach 1:
The heat pipe channel is segmented into multiple sections with different geometries (narrow section, wide section, curved section) along its length. This segmentation allows each section to perform specific functions: the narrow section promotes liquid return, the wide section enhances vaporization, and the curved section induces flow instability for oscillation, collectively achieving high heat transfer capability without requiring complex external systems
Solution Approach 2:
The patent transitions from conventional two-dimensional heat dissipation surfaces to a three-dimensional oscillating flow path within the heat pipe. The channel incorporates vertical curves, horizontal curves, and varying cross-sections that create complex 3D fluid dynamics, enabling enhanced heat transfer through volumetric utilization rather than just surface area
2Power
If the heat pipe channel has a uniform geometry, then the manufacturing is easier, but the vaporization and fluid flow stability are insufficient
Solution Approach 1:
Different sections of the heat pipe channel are designed with locally optimized geometries: the narrow section has smaller cross-section for liquid return, the wide section has larger cross-section for vigorous vaporization, and the curved sections have specific radii for flow instability. This local quality variation maximizes vaporization efficiency in each zone while maintaining manufacturability through standard fabrication techniques
3Power
If the heat pipe operates without flow oscillation, then the system is simpler, but the heat transfer coefficient is lower and the system overheats
Solution Approach 1:
The heat pipe channel geometry itself generates flow oscillation through inherent hydrodynamic instability. The combination of narrow and wide sections, along with curved portions, creates natural flow instabilities that drive self-sustained oscillations without requiring external actuators, control systems, or additional complexity. The system serves itself by using its own structure to generate the necessary flow dynamics
4Volume of moving object
If the channel cross-section is small, then the device can be miniaturized for portable electronics, but the heat dissipation capability is reduced
Solution Approach 1:
The heat pipe utilizes dynamic oscillating flow instead of static or steady flow. The flow continuously oscillates between liquid and vapor phases, creating time-varying heat transfer coefficients that are significantly higher than steady-state systems. This dynamic operation allows the compact channel to achieve high heat dissipation capability through temporal variations in flow behavior rather than relying on large cross-sectional area
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
Enhances heat transfer capabilities by up to 50% compared to existing solutions, reducing energy dissipation by 40-50% and providing efficient cooling for high-power electronics without the need for external power or energy sources.
Implementation Method 1
PHPs utilize both phase change and fluid motion to enhance heat transfer
Implementation Method 2
Heating of the contents of the micro-channel at an evaporator region (heat source) will induce further vaporization within the micro-channels
Implementation Method 3
cooling at a heat sink will induce further condensation within the micro-channels
Implementation Method 4
Heat is applied to the evaporator area/zone of the tubing resulting in increased vapor pressure and disrupting the equilibrium of the system
Implementation Method 5
As the vapor pressure increases, larger vapor bubbles are created and pulse from this high-pressure area
Implementation Method 6
Heat is dissipated using heatsinks and thermal diffusion covers formed from one or more of: high thermal conductivity metal
Implementation Method 7
Heat is dissipated using heatsinks and thermal diffusion covers formed from one or more of: high thermal conductivity metal, such as aluminum, copper
Data Source
Figure 1~2
Figure 3~4
Figure 5A~6
AI summary
A micro-channel pulsating heat pipe, preferably closed loop, includes a plate with micro-channels with obstructions along interior walls to increase surface area, add nucleation sites for the working fluid vaporization, and otherwise enhance fluid movement and heat transfer. Various shapes of obstructions are considered on one or more of the bottom wall, the side walls, and top wall of the channel Plating may fit over or around the plate to enhance strength and heat transfer. Ribbing, of a thermally conductive material, may set on the exterior surface of the plate and/or plating to enhance surface area to encourage heat transfer and arranged to facilitate air movement across exterior surface.