Heat Exchanger Fin Attachment and Turbulent Flow Design

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Solution Overview

Problem

In conventional fin-and-tube heat exchangers, the adhesive resin applied to heat transfer tubes can peel off when inserted into assembling holes, leading to deteriorated adhesion and a lower heat-transfer coefficient between the tubes and fins.

Innovation Solution

The heat exchanger design features ark-shaped contact surfaces on the fins that are bonded to the outer peripheral surface of the heat transfer tubes from the outside in a radial direction, preventing adhesive peeling and allowing for improved adhesion, along with strategically positioned fins to promote turbulent fluid flow for enhanced heat exchange.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If heat transfer tubes are inserted into assembling holes formed in fins, then the heat transfer tubes and fins can be fixedly attached, but the adhesive resin may be peeled and adhesion between the heat transfer tube and fin is deteriorated

Engineering Contradiction:
Improveadhesion between heat transfer tube and finVSAvoidheat-transfer coefficient
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

Instead of inserting the heat transfer tube into the fin as in conventional designs, the present invention attaches the fin to the outer peripheral surface of the heat transfer tube from the outside in a radial direction. This inversion of the assembly sequence prevents the heat transfer tube from contacting the assembling hole, thereby preventing adhesive peeling and maintaining reliable adhesion and heat-transfer coefficient.

Inventive Principle:
Principle #13The other way round (Inversion)

2Productivity

If fins are arranged in parallel with certain distance between them, then the structure is simple and easy to manufacture, but the heat exchange efficiency is reduced due to laminar fluid flow

Engineering Contradiction:
Improveheat exchange efficiencyVSAvoidfin arrangement complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The present invention employs asymmetric fin arrangements where adjacent fins are positioned at different locations in the tube axis direction, creating differences in level. This asymmetric configuration promotes turbulent fluid flow and enhances heat exchange efficiency without requiring complex additional components.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The invention utilizes the tube axis direction as an additional dimension for fin positioning, rather than only arranging fins in a single plane. By varying fin positions along the tube axis, the design creates three-dimensional flow patterns that promote turbulence and improve heat exchange efficiency.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 prevents adhesive peeling, maintains high adhesion between the heat transfer tubes and fins, and enhances the heat-transfer coefficient by promoting turbulent fluid flow, thereby improving heat exchange efficiency and providing earthquake resistance.

Implementation Method 1

an adhesive that bonds the outer peripheral surface of the heat transfer tube and the contact surface of each of the fins

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 2

it is possible to cause the fluid flowing around the difference in level to be a turbulent flow, which promotes heat exchange

Methodology Applied
Scientific EffectTurbulent flow: Turbulence

Data Source

PatentEP2843344B1Heat exchanger and heat exchanger manufacturing method
Publication Date: 2018.05.16 MITSUBISHI HEAVY IND LTD
  • EP2843344B1 patent drawingFigure 1
  • EP2843344B1 patent drawingFigure 2
  • EP2843344B1 patent drawingFigure 3~4

AI summary

A heat exchanger (1) includes a heat transfer tube (10); a plurality of fins (11) each having ark-shaped contact surfaces (17) configured to be brought into contact with an outer peripheral surface of the heat transfer tube (10), each of the fins (11) being attached from the outside in a radial direction of the heat transfer tube (10); an adhesive (21) that bonds the outer peripheral surface of the heat transfer tube (10) and the contact surface (17) of each of the fins (11); and a position regulation portion (22) which is provided between the fins (11) adjacent to each other in the tube axis direction and regulates a position in the tube axis direction of each of the fins (11).