Additively Manufactured Sacrificial Templates for Compact Heat Exchangers
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Solution Overview
Problem
Traditional heat exchanger manufacturing techniques struggle to combine multiple heat transfer enhancement features effectively, and additive manufacturing limitations, such as large minimum feature sizes and high production time, hinder the creation of compact, high-performance heat exchangers with thin walls.
Innovation Solution
The method involves additive manufacturing of a sacrificial scaffold, conformal coating to create heat exchanger walls, and subsequent removal of the scaffold, allowing for the production of heat exchangers with smaller passages and more compact structures, utilizing techniques like FDM, EBF3, DMLS, and SLM, and materials like metals, polymers, and ceramics, to enhance heat transfer while reducing pumping power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If additive manufacturing is used to directly print heat exchanger walls, then complex designs with multiple heat transfer enhancement features can be achieved, but wall thickness is limited to 50-100 microns minimum feature size resulting in high surface roughness and leaky walls
Solution Approach 1:
The manufacturing process is segmented into two distinct stages: first creating a sacrificial scaffold with the desired complex geometry, then coating it to form the final heat exchanger walls. This separation allows each stage to be optimized independently - the scaffold can have complex internal passages while the coating provides the precise, smooth final walls.
Solution Approach 2:
A sacrificial scaffold acts as an intermediary object that enables the formation of the final heat exchanger structure. The scaffold is temporarily created with complex geometry, coated to form the desired thin walls, then removed to leave clean passages. This intermediary approach allows achievement of both design complexity and manufacturing precision.
2Temperature
If thinner walls are produced to reduce conductive thermal resistance and increase heat transfer, then heat transfer performance improves, but additive manufacturing minimum feature size limits wall thickness to 50-100 microns
Solution Approach 1:
The sacrificial scaffold serves as a mediator that enables formation of thin walls beyond the additive manufacturing minimum feature size. By coating the scaffold rather than directly printing the walls, wall thickness is determined by coating control rather than printing resolution, achieving thinner, smoother walls for improved heat transfer.
Solution Approach 2:
The mechanical additive manufacturing process is replaced with a coating process for wall formation. Instead of building walls layer-by-layer with inherent roughness, a continuous coating is deposited over the scaffold, providing smooth, thin walls with controlled thickness independent of printing resolution.
3Ease of manufacture
If traditional heat exchanger fabrication techniques are used, then manufacturing is straightforward, but multiple heat transfer enhancement features cannot be effectively combined
Solution Approach 1:
The design and manufacturing are segmented into scaffold creation (handling complexity) and coating (providing simplicity). This allows complex multi-feature designs to be specified digitally while the coating process provides straightforward, uniform wall formation, combining design flexibility with manufacturing ease.
Solution Approach 2:
The manufacturing approach changes from direct mechanical fabrication to a coating-based process. This parameter change enables complex geometries to be defined by digital models while the coating process provides consistent, controllable wall formation, achieving both design versatility and manufacturing simplicity.
4Volume of moving object
If 3D printed heat exchangers with small feature sizes are produced, then compact structures with smaller passages can be achieved, but production time increases superlinearly
Solution Approach 1:
The production process is segmented so that the time-consuming additive manufacturing is performed only on the sacrificial scaffold, not the final heat exchanger walls. The coating step is much faster than printing fine features, enabling compact designs with smaller passages while maintaining high production rates.
Solution Approach 2:
The slow, resolution-limited additive manufacturing process is replaced with a faster coating process for wall formation. This substitution enables production of compact heat exchangers with small passages at high rates, as coating is much faster than printing fine features layer-by-layer.
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 approach enables heat exchangers with passage sizes 10 times smaller and 10 times more compact than previous 3D printed models, achieving higher heat transfer per unit volume and faster production rates, suitable for various thermal management applications.
Implementation Method 1
coating the sacrificial scaffold with a layer of the first material
Implementation Method 2
removing the sacrificial scaffold to leave behind the heat exchanger core
Data Source
AI summary
A method of manufacturing a heat exchanger including a heat exchanger core of a first material, the method including additive manufacturing a sacrificial scaffold of a second material, the sacrificial scaffold corresponding in shape to that of the heat exchanger core, coating the sacrificial scaffold with a layer of the first material, and removing the sacrificial scaffold to leave behind the heat exchanger core with an integrated self-aligned passage.