Lanced Offset Fin Heat Exchanger Design
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Solution Overview
Problem
Existing heat exchanger fins, such as louvered and split mini louvered fins, compromise structural integrity and increase material and manufacturing costs while limiting heat transfer efficiency, especially in applications requiring high heat transfer density and structural rigidity.
Innovation Solution
The design of lanced offset fins with angled walls and alternating valley and crest sections, which are offset between rows, enhances structural integrity and turbulence, thereby maximizing heat transfer efficiency while minimizing weight and material usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If louvered fins are used to increase turbulence and heat transfer efficiency, then heat transfer coefficient is improved, but fin weight and material usage increase
Solution Approach 1:
The fin surface is segmented into multiple rows of lances with alternating valley and crest sections, creating turbulence without requiring traditional louvered structures. This segmentation achieves heat transfer enhancement while using less material than conventional louvered fins.
Solution Approach 2:
The lances are positioned asymmetrically with alternating offset patterns between rows, and walls are angled at specific angles (e.g., 45 degrees) relative to the fin surface. This asymmetric configuration generates effective turbulence for heat transfer while minimizing material requirements compared to symmetric louvered designs.
2Temperature
If louvered fins are used to improve heat transfer efficiency, then heat transfer coefficient is improved, but structural integrity of heat exchange core deteriorates
Solution Approach 1:
The continuous fin surface is segmented into discrete lances separated by valleys, which maintains structural integrity while creating turbulence. The segmentation allows the fin to retain stiffness between lances rather than requiring material throughout the entire louvered structure.
Solution Approach 2:
Turbulence-generating features are localized to specific lance structures rather than being applied uniformly across the entire fin surface. This local quality approach concentrates heat transfer enhancement where needed while preserving overall structural integrity in other regions.
3Temperature
If mini louvered fins are used to extend full height for maximum efficiency, then heat transfer efficiency is improved, but cross-sectional flow area is compromised
Solution Approach 1:
Instead of protruding louvered structures that reduce flow area, the invention uses recessed valleys between lances that actually increase cross-sectional flow area. The turbulence is generated by the lance geometry and offset positioning rather than by protruding elements, inverting the traditional approach.
Solution Approach 2:
The lances extend through the full height of the fin, utilizing the vertical dimension to create turbulence along the entire flow path. This full-height configuration maximizes heat transfer efficiency without compromising cross-sectional flow area, as the turbulence is generated in the flow direction rather than by lateral protrusions.
4Strength
If lanced offset fins are used to increase structural rigidity, then structural integrity is improved, but heat transfer efficiency may be limited
Solution Approach 1:
The alternating offset pattern of lances between rows, combined with angled walls, creates asymmetric flow paths that generate turbulence and enhance heat transfer. This asymmetric configuration maintains structural rigidity while overcoming the heat transfer limitations of symmetric lanced fin designs.
Solution Approach 2:
The lance pitch, offset distance, and wall angles are optimized as specific parameters to simultaneously achieve structural rigidity and enhanced heat transfer. By carefully controlling these geometric parameters, both structural and thermal performance requirements are satisfied.
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 lanced offset fin configuration improves heat transfer efficiency and structural rigidity without increasing weight or material usage, effectively addressing the limitations of prior fin designs in applications like water-cooled charge air coolers with limited package sizes.
Implementation Method 1
The plurality of walls are interposed between and join the plurality of valley sections of the first row and the plurality of crest sections of the first row. At least one of the plurality of walls of the first row is angled with respect to a lateral axis of the member.
Data Source
AI summary
A fin for a heat exchanger includes a member and a first row formed in the member. The first row having a plurality of valley sections alternating with a plurality of crest sections. A plurality of walls is interposed between and integrally joins the plurality of valley sections and the plurality of crest sections. At least one of the plurality of walls of the first row is angled with respect to a lateral axis of the member. A second row is formed in the member, the second row having a plurality of valley sections alternating with a plurality of crest sections and a plurality of walls interposed between and integrally joining the plurality of valley sections to the plurality of crest sections.