Oblique-Finned Microchannels for Stable Two-Phase Heat Transfer
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Solution Overview
Problem
Flow boiling in micro-channels experiences instability due to pressure drop oscillations and premature critical heat flux, leading to reduced heat transfer efficiency and increased risk of thermal damage in electronic devices.
Innovation Solution
The use of an oblique-finned heat transfer device with angled channels that provide nucleate boiling regions and interrupt fully developed convective boiling regions, enhancing flow stability and delaying critical heat flux by allowing bubbles to escape through alternate pathways, thus reducing pressure fluctuations and increasing heat transfer coefficients.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If flow boiling heat transfer is used in micro-channels to dissipate high heat fluxes, then heat transfer performance is improved, but pressure drop oscillations and flow instability occur
Solution Approach 1:
The micro-channel is segmented into multiple sections with alternating heated and unheated regions. This segmentation disrupts the continuous boiling process, preventing large pressure oscillations while maintaining high heat flux dissipation in the heated sections.
Solution Approach 2:
The invention introduces a spatial dimension variation by creating oblique channels at angles to the primary flow direction. This geometric modification alters the two-phase flow patterns, enhancing heat transfer while stabilizing pressure fluctuations through controlled bubble departure angles.
2Stability of the object's composition
If throttling control valve is used to suppress pressure drop oscillations, then flow boiling stability is improved, but pressure drop penalty increases
Solution Approach 1:
The micro-channel geometry itself provides flow stabilization through its segmented heated sections and oblique angle configuration. The structure passively regulates two-phase flow without requiring external control valves, eliminating the additional pressure drop penalty that would be imposed by throttling devices.
3Ease of manufacture
If straight fins are used in heat transfer device, then manufacturing is simple, but heat transfer performance and flow boiling stability are limited
Solution Approach 1:
The invention employs oblique fins angled relative to the base surface, creating asymmetric flow channels. This asymmetric geometry enhances heat transfer coefficients by promoting better liquid distribution and bubble departure characteristics, while still maintaining manufacturability through standard fabrication techniques.
Solution Approach 2:
The oblique fin configuration creates curved flow paths and non-uniform velocity distributions that enhance mixing and heat transfer. The curved geometry promotes more effective bubble-liquid interaction compared to straight fins, improving overall heat transfer performance.
4Productivity
If critical heat flux is reached to maximize heat dissipation, then heat transfer efficiency is improved, but thermal damage risk increases
Solution Approach 1:
The segmented heated sections and oblique channel geometry preemptively control bubble formation and departure patterns. This prevents the sudden, uncontrolled vapor generation that leads to critical heat flux conditions, thereby avoiding thermal damage while maintaining efficient heat dissipation through controlled two-phase 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 oblique-finned design significantly augments heat transfer performance, delays critical heat flux, and stabilizes the flow boiling process, achieving higher heat flux dissipation with reduced pressure drop fluctuations and uniform temperature distribution.
Implementation Method 1
walls defining the primary and oblique spaces provide nucleate boiling regions
Implementation Method 2
the interruption of fully developed convective boiling regions
Implementation Method 3
Device and method for a two phase heat transfer
Data Source
AI summary
The invention provides a two phase heat transfer device comprising an inlet for receiving a heat transfer fluid, and; an array of heat transfer fins in spaced relation; primary spaces between said heat transfer fins defining primary channels parallel to a path from the inlet to outlet, and; oblique spaces between said heat transfer fins defining oblique channels arranged at an angle to said primary channels. It is preferable that walls defining the primary and oblique spaces provide nucleate boiling regions and the interruption of fully developed convective boiling regions when a heat transfer fluid is passed through the inlet to the outlet.