Minimal Surface Heat Exchanger Core for Thermal Stress Compliance

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Solution Overview

Problem

Traditional heat exchanger designs using straight geometry building blocks suffer from low compliance, leading to mismatched strain and high stresses under nonlinear thermal gradients, with inadequate heat transfer, pressure loss, and vibration response.

Innovation Solution

A monolithic heat exchanger core design utilizing three-dimensional minimal surfaces with independently scalable unit cells, allowing for customized adjustments along orthogonal axes using implicit surface approximations and additive manufacturing processes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If traditional straight geometry building blocks are used, then ease of manufacture is improved, but heat transfer performance and structural compliance deteriorate

Engineering Contradiction:
Improveease of manufactureVSAvoidheat transfer performance
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The patent applies curved minimal surface geometries (triply periodic minimal surfaces or TPMS) to replace traditional straight geometry building blocks. These curved surfaces create continuous, smooth transitions that improve heat transfer efficiency and structural compliance while maintaining manufacturability through advanced fabrication techniques.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The patent utilizes parametric design to vary geometric parameters of the unit cells, allowing optimization of heat transfer surfaces, flow channels, and structural properties. By changing parameters such as surface curvature, cell size, and orientation, the design achieves superior heat transfer performance and adaptability to thermal gradients.

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If traditional straight geometry building blocks are used, then ease of manufacture is improved, but thermal stress resistance deteriorates

Engineering Contradiction:
Improveease of manufactureVSAvoidthermal stress
Core Design Contradiction:
Ease of manufactureVSStress or pressure

Solution Approach 1:

The curved minimal surface geometries provide smooth transitions and continuous structures that distribute thermal stresses more evenly throughout the component. The absence of sharp corners and discontinuities in the TPMS design reduces stress concentration points, improving resistance to thermal fatigue and failure.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The parametric design allows local optimization of geometric properties in different regions of the heat exchanger. Areas subject to higher thermal gradients or stresses can have adjusted surface densities, wall thicknesses, or cell configurations to provide enhanced local strength and compliance where needed.

Inventive Principle:
Principle #3Local quality

3Ease of manufacture

If symmetrical unit cell dimensions are used, then manufacturing simplicity is improved, but adaptability to thermal gradients deteriorates

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidadaptability to thermal gradients
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The patent employs asymmetrical unit cell designs where dimensions along different axes are independently variable. This allows the creation of non-uniform geometric configurations that can be optimized for specific thermal gradient directions and magnitudes, enabling the heat exchanger to adapt to varying operational conditions and thermal loads.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

Different regions of the heat exchanger can have differently sized or shaped unit cells tailored to local thermal conditions. Areas with higher heat flux can have increased surface area density, while regions with lower demands can have reduced complexity, optimizing overall performance across the entire component.

Inventive Principle:
Principle #3Local quality

4Productivity

If three-dimensional parametric control is implemented, then heat transfer performance is improved, but device complexity increases

Engineering Contradiction:
Improveheat transfer performanceVSAvoiddevice complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The complex three-dimensional parametric design is broken down into repeating unit cells that can be generated through systematic variation of a base geometry. This modular approach allows complex overall configurations to be built from simpler standardized components, facilitating manufacturing and analysis while maintaining high heat transfer performance.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP4253899B1Minimal surface core heat exchangers with three-dimensional parametric control
Publication Date: 2026.04.29 HAMILTON SUNDSTRAND CORP
  • EP4253899B1 patent drawingFigure 1
  • EP4253899B1 patent drawingFigure 2~3
  • EP4253899B1 patent drawingFigure 3A~3H

AI summary

A monolithic core (12) for a heat exchanger comprises a plurality of three-dimensional unit cells (22) arranged along three orthogonal axes of the core, the three orthogonal axes comprising a first axis, a second axis, and a third axis. Each of the plurality of unit cells has a first dimension comprising an axial extent along the first axis, a second dimension comprising an axial extent along the second axis, and a third dimension comprising an axial extent along the third axis. For at least one unit cell of the plurality of unit cells, the first dimension is not equal to the second dimension.