Heat Exchanger Brazed End Flange Attachment Design
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Solution Overview
Problem
The raised edges of end flanges in heat exchangers reduce the surface area for contact and brazing, leading to attachment defects, particularly in thin heat exchangers with a thickness between 12 and 18 mm.
Innovation Solution
The design includes a flat body with attachment tabs and extensions that increase the surface area for brazing, where the width between attachment tabs is less than the width of the extensions, allowing for improved attachment and integration with the heat exchange bundle, while maintaining a hooking rim for aerodynamic elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the edges of the end flange are raised to form a rim for attaching aerodynamic elements, then the attachment capability for aerodynamic elements is improved, but the surface area for brazing between the end flange and the heat exchange bundle is reduced
Solution Approach 1:
The invention extends the flat body of the end flange in the width direction beyond the heat exchange bundle, creating additional brazing surface area in a different dimensional space. This extension allows the brazing surface to be enlarged without interfering with the rim's attachment function, effectively resolving the contradiction between attachment capability and brazing surface area by utilizing additional spatial dimension.
Solution Approach 2:
The end flange is segmented into distinct functional zones: the rim portion for aerodynamic element attachment and the extended flat body portion for brazing. This segmentation allows each zone to independently fulfill its specific function without compromising the other, enabling the rim to provide attachment capability while the extended portion provides sufficient brazing surface area.
2Device complexity
If the width of the flat body between attachment tabs is reduced to accommodate rim structure, then the attachment structure for aerodynamic elements is simplified, but the useful surface area for brazing is reduced leading to attachment defects
Solution Approach 1:
The flat body is extended in the width direction beyond the heat exchange bundle boundaries, creating additional brazing surface area in the lateral dimension. This dimensional extension provides sufficient brazing area without complicating the attachment tab structure, maintaining simplicity while ensuring reliable brazing attachment.
3Reliability
If the end flange width is increased to provide more brazing surface area, then the brazing attachment reliability is improved, but the overall size of the heat exchanger is increased
Solution Approach 1:
The end flange design implements local quality by extending the flat body only in the width direction where additional brazing surface is needed, while maintaining the original thickness and length dimensions. This localized extension provides the necessary brazing area without proportionally increasing the overall heat exchanger size, as the extension is confined to a specific regional dimension rather than uniformly increasing all dimensions.
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 design enhances the attachment of end flanges to the heat exchange bundle, providing a larger surface area for brazing and improved attachment, especially beneficial for thin heat exchangers, while maintaining structural integrity and aerodynamic functionality.
Implementation Method 1
an end flange arranged on each side of the stack of tubes, said end flange being brazed to the heat exchange bundle
Data Source
AI summary
A heat exchanger for a motor vehicle includes heat exchange bundle with a plurality of stacked tubes inside which a first heat-transfer fluid circulates, and an end flange arranged on each side of the stack of tubes which brazed to the heat exchange bundle. The end flanges include a flat body with a first surface that faces an aerodynamic element and a second surface, the brazing surface, opposite to the first surface and brazed to the heat exchange bundle. Attachment tabs receive the aerodynamic element and are arranged on the sides of the flat body, the attachment tabs projecting in the opposite direction to the heat exchange bundle. At least one extension of the flat body extends in the same general plane as the flat body and is arranged between a pair of attachment tabs on a same side of the flat body.