Corrugated-Fin Heat Exchanger Drainage Structure for Faster Water Removal
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Solution Overview
Problem
The existing drain structures for corrugated-fin heat exchangers, which form water flow passages by obliquely cutting and raising flange portions, are limited in effectiveness due to constraints on the size and angle of the lug pieces, leading to insufficient drainage, especially when the heat exchange tube thickness is large or the fin pitch is increased, resulting in reduced heat exchange performance.
Innovation Solution
The proposed drain structure enhances drainage by forming water flow passages with lug pieces that have a width at least 2 mm, a thickness of 0.2 to 0.8 mm, and an angle that satisfies the relationship L×sin θ=T, allowing for increased contact with retained water and improved drainage, along with additional features like a side plate with a drain slit and angled vertical pieces with drain ditches to facilitate water flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the fin pitch is increased to improve water retention property, then drainage capability is improved, but the area of heat transfer on the air side is reduced
Solution Approach 1:
The invention divides the drainage function into multiple segments by providing multiple water flow passages formed by lug pieces at different positions along the heat exchange tube. This segmentation allows effective drainage with smaller individual fin pitches, thereby maintaining heat transfer area while improving water retention property
Solution Approach 2:
The invention transitions from a single-dimensional drainage approach to a multi-dimensional solution by arranging lug pieces both along the longitudinal direction and at different angular positions. This dimensional expansion enables effective drainage without requiring increased fin pitch, thus preserving heat transfer area
2Reliability
If the angle of cutting and raising the flange portions is small to secure given drainage, then the drain rate is extremely decreased
Solution Approach 1:
The invention optimizes the angle of the lug pieces to dynamically balance drainage capability and drain rate. By setting the angle within a specific range (10° to 45°), the structure achieves both reliable drainage and high drain rate, resolving the contradiction between stability and efficiency
Solution Approach 2:
The invention changes the angular parameter of the lug pieces from a small fixed angle to an optimized range (10° to 45°). This parameter adjustment simultaneously improves both drainage capability and drain rate, eliminating the trade-off between the two features
3Reliability
If the width of lug pieces is increased to improve drainage, then contact area with water increases, but the structural integrity of heat exchange tube may be compromised
Solution Approach 1:
The invention applies partial action by providing multiple lug pieces at strategically positioned intervals rather than one large lug piece. This distribution of drainage function across multiple smaller elements maintains structural integrity while achieving effective drainage through cumulative contact area with water
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 configuration significantly increases the drain rate and enhances drainage efficiency, even with larger heat exchange tubes and increased fin pitches, by ensuring that water droplets are effectively induced and drained from the corrugated fins, thereby improving heat exchange performance and reducing airflow resistance.
Implementation Method 1
water droplets are effectively induced and drained from the corrugated fins
Implementation Method 2
condensed water (dew water) adheres to the surface thereof
Data Source
AI summary
A corrugated-fin heat exchanger is constructed by arranging a plurality of flat heat exchange tubes parallel to each other in a horizontal direction between a pair of opposing header pipes, joining, at a position between the plurality of flat heat exchange tubes, corrugated fins formed by alternately repeating peak folding and valley folding portions, and forming water flow passages from lug pieces that are obtained by obliquely cutting and raising flange portions extending along end portions of each of the plurality of flat heat exchange tubes (3) in a width direction thereof. A pitch (P) of each of the corrugated fins between a peak and a valley thereof, a width (L) of each of the lug pieces in a vertical direction thereof, and a thickness (T) of the each of the plurality of flat heat exchange tubes have a relationship of P×2≧L≧T.