Flat-Tube Heat Exchanger Fin Layout for Airflow and Drainage
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Solution Overview
Problem
Existing heat exchangers face challenges in reducing air flow resistance while maintaining drainability of condensed water and ensuring stable fin pitch, as the arrangement of raised-lance elements perpendicular to air flow direction increases resistance, but parallel arrangement decreases drainability.
Innovation Solution
A heat exchanger design featuring flat tubes inserted into notches of heat transfer fins with standing portions on the periphery, arranged to avoid facing each other across a reference line, providing stability and strength, and allowing for alternate or wave-shaped configurations to optimize fin pitch and air flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the raised-lance element is disposed perpendicular to the air flow direction to secure fin pitch, then the fin pitch is maintained, but the air flow resistance increases
Solution Approach 1:
The patent applies asymmetry by arranging the standing portions (replacing raised-lance elements) in a non-symmetric pattern relative to the air flow direction. Specifically, the standing portions are positioned at locations that do not create perpendicular obstacles to air flow, thereby reducing air flow resistance while still maintaining the necessary fin pitch through their strategic asymmetric placement.
Solution Approach 2:
The patent transitions from a single-dimension approach (perpendicular raised-lance elements) to a multi-dimensional arrangement by positioning standing portions at various locations around the flat tube perimeter. This dimensional change allows the standing portions to maintain fin pitch in multiple directions while avoiding perpendicular alignment with air flow, thus reducing resistance.
2Object-affected harmful factors
If the raised-lance element is arranged parallel to the air flow direction to reduce air flow resistance, then the air flow resistance decreases, but the drainability of condensed water decreases
Solution Approach 1:
The patent applies local quality by providing standing portions at specific localized positions around the flat tube rather than using a uniform arrangement. This allows certain standing portions to be positioned to facilitate water drainage while others are positioned to minimize air flow resistance, creating different local functions within the same structure.
Solution Approach 2:
The patent segments the fin pitch maintenance function into multiple standing portions distributed around the flat tube perimeter. This segmentation allows different standing portions to serve different purposes: some primarily maintain fin pitch, others facilitate drainage, and others minimize air flow resistance, thereby resolving the contradiction between drainage and air flow.
3Volume of moving object
If thin flat tubes are used to reduce size, then the heat exchanger size decreases, but the strength of brazed heat transfer fins becomes insufficient
Solution Approach 1:
The patent applies preliminary action by providing multiple standing portions that pre-establish support and stabilization for the thin flat tubes before brazing operations. These standing portions act as preliminary structural reinforcements that prevent deformation and provide stable positioning during the brazing process, enabling successful brazing of thin-walled tubes that would otherwise be too fragile.
Solution Approach 2:
The patent effectively creates a composite structural system where the standing portions (protruding from heat transfer fins) and the thin flat tubes work together as an integrated assembly. The standing portions provide additional structural support that compensates for the thin wall thickness, creating a composite structure with sufficient overall strength despite using thin materials.
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 design reduces air flow resistance and maintains high drainability of condensed water, ensuring stable fin pitch and strength, while accommodating thin flat tubes and improving manufacturing efficiency and product quality.
Implementation Method 1
a heat exchanger including a plurality of flat tubes (21, 21A) and a plurality of heat transfer fins (31, 31A)... exchanging heat between air and refrigerant
Implementation Method 2
heat transfer fins (31, 31A)... air flow direction... exchanging heat between air and refrigerant
Data Source
Figure 1
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AI summary
In a heat exchanger in which a flat tube is inserted into a notch of a heat transfer fin, a high-quality heat exchanger can be provided in which an increase in air flow resistance and deterioration of drainability of condensed water can be reduced and fin pitch can be secured. A plurality of heat transfer fins (31) each have a plurality of notches (35) that receive a plurality of flat tubes along a width direction of the flat tubes. The plurality of heat transfer fins (31) each includes three standing portions (61, 62, 63) provided on a peripheral portion of each of the notches (35) for forming a gap with adjacent heat transfer fins (31). The three standing portions (61, 62, 63) are arranged so as not to face each other across a reference line RL that extends in the width direction through a perpendicular center portion of the flat tube.