Heat Exchanger Louver Height Variation for Compact Fin Design
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Solution Overview
Problem
Existing heat exchangers face challenges in maintaining equal louver heights in fins, leading to shape deformation and reduced heat exchange performance, particularly when the fin width is narrowed, causing fluid stagnation and inefficient heat transfer.
Innovation Solution
The heat exchanger design incorporates fins with varying louver heights, where higher louvers have shorter tip ends and are shaped using rollers with different cutting blade heights to minimize deformation during manufacturing, ensuring that all louvers are cut simultaneously to maintain even contact and prevent material pulling, thus maintaining optimal heat exchange performance even at narrower widths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the fin width is narrowed to improve compactness, then the heat exchanger size is reduced, but the clearance between louvers becomes smaller causing fluid stagnation and reduced heat exchange performance
Solution Approach 1:
The patent applies local quality by varying the louver height along the fin width direction. Specifically, the louver height is made larger at the center portion of the fin and smaller at the both-end portions. This local differentiation allows the central region to maintain larger clearance for fluid flow while the end regions can be narrower, thus achieving compact overall size without causing fluid stagnation in the clearance between louvers
Solution Approach 2:
The patent employs asymmetry by creating non-uniform louver heights across the fin width. The louver configuration is asymmetric with respect to height distribution, with taller louvers at the center and shorter louvers at the ends. This asymmetric design optimizes the balance between compactness and heat exchange performance by preventing fluid stagnation in the critical central region while minimizing the overall fin width
2Productivity
If the louver heights are made unequal to prevent fluid stagnation, then heat exchange performance is improved, but shape deformation occurs during roller shaping manufacturing
Solution Approach 1:
The patent applies parameter changes by systematically varying the louver height parameter along the fin width direction. The louver height is changed from a uniform value to a gradient distribution where the height is larger at the center and smaller at the ends. This controlled parameter change achieves the dual objectives of preventing fluid stagnation (improving heat exchange performance) and managing the manufacturing implications of non-uniform geometry
Solution Approach 2:
The patent incorporates preliminary action by designing the louver height variation in advance during the manufacturing planning stage. The non-uniform louver heights are predetermined in the fin design, allowing the roller shaping process to be configured accordingly. This preliminary design consideration enables the manufacturing process to accommodate the varying louver heights while minimizing shape deformation through proper tooling and process parameter selection
3Manufacturing precision
If equal louver heights are used to simplify manufacturing, then manufacturing precision is maintained, but fluid stagnation occurs reducing heat exchange performance
Solution Approach 1:
The patent resolves this contradiction by applying local quality - making different parts of the fin have different louver heights. The center portion has larger louver heights to prevent fluid stagnation and enhance heat exchange performance, while the both-end portions have smaller louver heights. This local differentiation maintains manufacturing feasibility while eliminating the fluid stagnation problem that would occur with uniform equal-height louvers
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 heat exchange performance by reducing shape deformation and fluid stagnation, allowing for efficient heat transfer while maintaining a compact fin width, thereby improving the overall efficiency of the heat exchanger.
Implementation Method 1
a fin bonded to the tubes to promote heat exchange between the first fluid and a second fluid
Implementation Method 2
heat exchange between the first fluid and a second fluid that flows along one direction through spaces among the tubes
Data Source
AI summary
In a heat exchanger, when louvers are viewed from an airflow direction, a louver tip end width becomes shorter with increase of a louver height. A fin width of the fin is 14 mm or shorter. Airflow-end louver lengths of an upstream-end first louver, a downstream-end first louver, an upstream-end second louver, and a downstream-end second louver are “⅝×LP” or longer, where LP is a louver pitch.