Louvered Fin Geometry for Heat Exchanger Pressure Drop
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Solution Overview
Problem
Existing heat exchangers face challenges in maximizing airflow while minimizing pressure drop, which affects thermal efficiency and heat transfer rates.
Innovation Solution
The design of high-performance heat exchanger fins with varying louver widths and angles, featuring a turnaround rib and entrance and exit louvers, helps in minimizing pressure drop and maximizing airflow by optimizing the airflow pattern and reducing frictional losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If louvered fins are formed at a predetermined angle to improve thermal efficiency, then heat transfer rate increases, but pressure drop increases
Solution Approach 1:
The patent applies local quality by varying the louver angle along the fin length. Entrance louvers have a first angle (e.g., 10-20 degrees) to minimize pressure drop, while exit louvers have a second angle (e.g., 30-45 degrees) to maximize heat transfer. This local differentiation resolves the contradiction by optimizing each section's function rather than using a uniform angle throughout.
Solution Approach 2:
The fin is segmented into multiple sections with different louver configurations. The fin includes an entrance section with entrance louvers, a middle section with turnaround ribs, and an exit section with exit louvers. Each segment has optimized characteristics for its specific function, allowing the overall system to achieve both low pressure drop and high heat transfer rate.
2Productivity
If airflow direction is changed multiple times through louvers and turnaround ribs, then thermal efficiency improves, but pressure drop increases
Solution Approach 1:
The patent applies preliminary action by gradually changing the airflow direction through staged louvers rather than abrupt turns. The entrance louvers begin the direction change at a shallow angle, and the turnaround ribs in the middle section continue the gradual redirection. This progressive approach minimizes flow separation and pressure losses while achieving the necessary direction change for thermal efficiency.
3Productivity
If fin surface area is increased to maximize heat transfer, then thermal efficiency improves, but pressure drop increases
Solution Approach 1:
The patent applies parameter changes by optimizing the louver geometry parameters (angle, spacing, width) to achieve maximum heat transfer with minimum pressure drop. The specific parameter combinations tested and disclosed represent optimized values that balance surface area utilization with flow resistance, resolving the contradiction between these two competing requirements.
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 achieves a 15% reduction in pressure drop and enhances thermal efficiency by maximizing airflow and exposed surface area, thereby improving heat transfer rates.
Implementation Method 1
heat in a fluid flowing through the tubes is conducted through the walls of the tubes, into the fins, and transferred into the air
Implementation Method 2
Air is directed across the fins of the heat exchanger by a cooling fan or a motion of a vehicle, for example. As the air flows across the fins, heat in a fluid flowing through the tubes is conducted through the walls of the tubes, into the fins, and transferred into the air
Data Source
AI summary
A high performance louvered fin for a heat exchanger is disclosed, wherein adjacent entrance louvers have increased widths and adjacent exit louvers have decreased widths in order to optimize thermal efficiency.