Micro-channel Cold Plate Orifice Flow Balancing
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Solution Overview
Problem
Conventional micro-channel cold plates experience coolant flow misdistribution due to uneven vapor fraction across parallel flow paths, leading to pressure drop imbalances and reduced thermal performance when dealing with varying heat loads, as flow paths with higher heat loads are starved of fluid flow.
Innovation Solution
The implementation of a cold plate system with parallel flow paths and strategically sized and spaced orifices to minimize mass flow rate differences between paths, ensuring balanced coolant distribution by using orifices that prevent flashing and adjust pressure drops to maintain optimal flow rates across paths with varying heat loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional parallel micro-channel flow paths are used for phase-change cooling, then the system achieves high heat dissipation capability, but coolant flow misdistribution occurs due to uneven vapor fraction causing pressure drop imbalances
Solution Approach 1:
The patent applies local quality by introducing orifices at specific locations within parallel flow paths to create localized pressure drop adjustments. Each orifice is strategically positioned to address the specific vapor fraction accumulation issues in particular channel sections, allowing different parts of the system to have tailored flow resistance characteristics that compensate for uneven heat loads and vapor generation rates.
Solution Approach 2:
The patent changes the flow resistance parameter by incorporating orifices with specific dimensions and configurations. By adjusting orifice size, shape, and placement, the system modifies local pressure drop characteristics to balance the overall flow distribution. This parameter adjustment compensates for the varying vapor fractions and heat loads across different parallel paths, maintaining reliable coolant distribution while preserving high heat dissipation capability.
2Power
If flow paths with higher heat loads receive more vapor fraction, then heat dissipation efficiency increases, but pressure drop increases causing flow starvation in those paths
Solution Approach 1:
The patent applies preliminary anti-action by placing orifices upstream or at strategic points before vapor fraction becomes excessively high. These orifices create preliminary pressure drops that preemptively counteract the tendency for vapor accumulation and subsequent flow starvation. By acting in advance, the orifices prevent the development of severe pressure imbalances that would otherwise cause flow paths with high heat loads to starve of coolant.
Solution Approach 2:
The patent employs asymmetry by designing orifices with different characteristics (size, shape, orientation) in different parallel flow paths based on their specific heat load requirements. Flow paths with higher heat loads and greater vapor generation receive orifices with larger flow capacity or different geometries compared to paths with lower heat loads. This asymmetric configuration balances the overall system performance by compensating for the unequal thermal conditions across parallel paths.
3Reliability
If complex active component flow-balancing devices are used to balance coolant flow, then flow distribution uniformity improves, but device complexity and mechanical component size increase
Solution Approach 1:
The patent extracts the flow balancing function from complex active mechanical components and implements it through simple passive orifices. By removing the need for springs, diaphragms, and other active elements, the system achieves flow distribution uniformity through carefully designed geometric features that are integral to the cold plate structure. This extraction simplifies the overall device while maintaining reliable coolant flow balance across parallel paths.
Solution Approach 2:
The patent applies self-service by designing orifices that automatically adjust flow distribution based on local conditions without requiring external control mechanisms. The orifices passively respond to pressure and vapor fraction variations, self-regulating the coolant flow balance across parallel paths. This eliminates the need for complex active control systems, reducing device complexity while maintaining flow distribution uniformity through the inherent physical properties of the orifice structures.
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
This solution effectively prevents flow starvation and maintains thermal performance by offsetting pressure drop reductions through orifice-induced pressure increases, ensuring robust and efficient cooling even under spatially and temporally varying heat loads, enhancing heat flux dissipation and thermal performance.
Implementation Method 1
the first orifice is sized to not cause flashing of the liquid coolant and the second orifice is sized to flash subcooled liquid coolant to a two-phase flow
Implementation Method 2
Micro-channel cold plates utilizing phase-change heat removal have emerged as a viable technique for coping with increased dissipation density in semiconductor devices
Implementation Method 3
the first and second flow paths enable two-phase coolant flow under pressure through micro-channels for cooling heat loads on the cold plate system
Data Source
AI summary
A cold plate system including, in one embodiment, first and second flow paths extending from a common inlet to a common outlet, wherein the first and second flow paths enable two-phase coolant flow under pressure through micro-channels for cooling heat loads on the cold plate system, first and second orifices disposed in the first flow path on an inlet side of the first flow path, and a third orifice spaced from a fourth orifice, the third and fourth orifices disposed in the second flow path on an inlet side of the second flow path, wherein the first and second orifices in the first flow path and the third and fourth orifices in the second flow path minimize a difference in mass flow rate between the first and second flow paths when the first and second flow paths are exposed to different heat loads.