Multiple-Porosity Cooling Assemblies for Power Electronics
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current cooling assemblies for heat generating devices, such as power semiconductor devices, lack sufficient nucleation site density for enhanced thermal performance in two-phase cooling systems.
Innovation Solution
A cooling assembly featuring a heat transfer substrate with alternating arrays of metal fibers, creating a multiple-porosity structure that includes macro-porosity from the fiber arrangement and micro-porosity from the metal particles, which increases nucleation sites and heat transfer efficiency through capillary-assisted fluid flow and vapor escape paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional cooling assemblies use smooth or single-level porous surfaces, then the structure is simple to manufacture, but the nucleation site density is insufficient for enhanced thermal performance
Solution Approach 1:
The patent applies porous materials by incorporating a porous layer with controlled porosity (30-70%) on the cooling assembly surface. This porous structure provides increased nucleation site density for bubble formation during two-phase heat transfer, directly improving thermal performance while the porosity level can be optimized to balance performance with manufacturing complexity
Solution Approach 2:
The patent uses composite materials by combining a base cooling assembly surface with an additional porous layer made of different material properties. This composite structure integrates the functional benefits of high nucleation site density with the structural integrity of the original cooling assembly, resolving the contradiction between thermal performance and manufacturing simplicity
2Reliability
If rough or porous surfaces are added to increase nucleation sites, then heat transfer performance is enhanced, but manufacturing complexity increases
Solution Approach 1:
The patent segments the cooling assembly into distinct functional layers: a base cooling assembly and a separate porous layer. This segmentation allows the porous layer to be manufactured independently using optimized processes, then integrated with the base structure, thereby improving heat transfer performance while managing manufacturing complexity through modular construction
Solution Approach 2:
The patent applies parameter changes by controlling the porosity of the porous layer within a specific range (30-70%). This parameter optimization balances the competing requirements: sufficient porosity to provide high nucleation site density for enhanced heat transfer, while maintaining porosity levels that are achievable through conventional manufacturing processes
3Reliability
If multiple arrays of metal fibers are used to create multiple-porosity structure, then nucleation site density and vapor escape paths are increased, but device complexity increases
Solution Approach 1:
The patent applies the nesting principle by creating a hierarchical porous structure with multiple arrays of metal fibers arranged at different scales and orientations. The finer fibers are nested within the framework of coarser fibers, creating multiple porosity levels that provide both high nucleation site density and efficient vapor escape paths while maintaining structural integrity
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 multiple-porosity structure enhances two-phase heat transfer by increasing nucleation sites, available heat transfer area, and vapor escape paths, leading to improved thermal performance and efficiency in cooling heat generating devices.
Implementation Method 1
heat transfer is provided by the phase-change of the cooling fluid from a liquid to a vapor by nucleation. Rough or porous surfaces provide additional nucleation sites to encourage boiling
Implementation Method 2
increased heat transfer efficiency through capillary-assisted fluid flow
Implementation Method 3
Heat generating devices, such as power semiconductor devices, may be coupled to a heat spreader to remove heat and lower the maximum operating temperature
Data Source
AI summary
Cooling assemblies and power electronics modules having multiple-level porosity structures with both a micro- and macro-level porosity are disclosed. In one embodiment, a cooling assembly includes a jet impingement assembly including a fluid inlet channel fluidly coupled an array of orifices provided in a jet plate, and a heat transfer substrate having a surface. The heat transfer substrate is spaced apart from the jet plate. A first array of metal fibers is bonded to the surface of the heat transfer substrate in a first direction, and a second array of metal fibers is bonded to the first array of metal fibers in a second direction. Each metal fiber of the first array of metal fibers and the second array of metal fibers includes a plurality of metal particles defining a micro-porosity. The first array of metal fibers and the second array of metal fibers define a macro-porosity.