Heat Exchanger Insert with Serpentine Fold and Dimples

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Solution Overview

Problem

Conventional heat exchangers face challenges in efficiently transferring heat between working fluids due to limitations in flow path separation and surface area enhancement, leading to suboptimal heat transfer efficiency and durability.

Innovation Solution

The heat exchanger design incorporates a pair of spaced headers with tubes and an insert having a serpentine fold with dimples and protrusions, enhancing the flow path and surface area for improved heat transfer and durability, while maintaining separate flow paths for the working fluids.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional heat exchanger designs are used with simple tube structures, then manufacturing is easier and device complexity is lower, but heat transfer efficiency is insufficient due to limited surface area and flow path separation

Engineering Contradiction:

Improveheat transfer efficiencyVSAvoidinsert structure complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The heat exchanger is divided into multiple tubes, each containing separate inserts for hot and cold fluid flow paths. This segmentation allows independent optimization of each flow path while maintaining overall system efficiency. The inserts are segmented with multiple legs and dimples to create distinct flow channels.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Inserts are placed inside the tubes, creating a nested structure where the insert is contained within the tube. This nesting approach allows the insert to enhance the tube's heat transfer capability without adding external complexity. Multiple inserts can be nested within single tubes to handle multiple fluid streams.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Productivity

If inserts with folds and dimples are added to enhance surface area and turbulence, then heat transfer efficiency improves, but manufacturing complexity and assembly difficulty increase

Engineering Contradiction:

Improveheat transfer efficiencyVSAvoidinsert manufacturing and assembly

Core Design Contradiction:

ProductivityVSEase of manufacture

Solution Approach 1:

The inserts are formed from flexible metal sheets that are folded and shaped into complex three-dimensional configurations with folds and dimples. This approach allows complex geometries to be manufactured from simple flat sheets using forming operations, rather than requiring complex machining or assembly of multiple parts. The flexibility of the thin metal material enables the creation of serpentine folds and dimpled surfaces that would be difficult to manufacture otherwise.

Inventive Principle:

Principle #30Flexible shells and thin films

3Productivity

If flow path separation is improved with multiple inserts, then heat transfer between working fluids is enhanced, but pressure buildup may occur

Engineering Contradiction:

Improveheat transfer efficiencyVSAvoidpressure buildup in flow paths

Core Design Contradiction:

ProductivityVSStress or pressure

Solution Approach 1:

The inserts feature curved serpentine folds and dimpled surfaces rather than sharp angular changes. These curved geometries guide fluid flow smoothly through the insert structure, reducing turbulence-induced pressure drops and preventing stagnant zones where pressure buildup could occur. The continuous curvature of the serpentine path maintains steady flow velocity.

Inventive Principle:

Principle #14Spheroidality (Curvature)

4Device complexity

If simple tube structures are used, then device complexity is lower, but flow path separation between hot and cold fluids is insufficient

Engineering Contradiction:

Improveheat exchanger structureVSAvoidflow path separation

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The tube wall acts as an intermediary barrier between the hot and cold fluid flow paths. The inserts within each tube further separate the flow paths by providing dedicated channels for hot and cold fluids. This multi-layer separation approach ensures reliable thermal isolation while maintaining compact design.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 increases turbulence and heat transfer efficiency without significant pressure buildup, improving the durability and strength of the heat exchanger, and allowing for efficient heat exchange between high and low-temperature working fluids.

Implementation Method 1

This configuration increases turbulence and heat transfer efficiency without significant pressure buildup

Methodology Applied

Scientific EffectTurbulence: Turbulence

Implementation Method 2

heat exchanger for transferring heat between a first working fluid and a second working fluid

Methodology Applied

Scientific EffectHeat transfer: Conduction (thermal)

Data Source

PatentUS8516699B2Method of manufacturing a heat exchanger having a contoured insert

Publication Date: 2013.08.27 MODINE MFG CO

AI summary

A heat exchanger for transferring heat between a first working fluid and a second working fluid, including a pair of spaced apart headers, a number of tubes extending between the pair of headers and providing a flow path for the first working fluid and being positioned along a flow path for the second working fluid, and an insert supportable in one of the tubes and having a fold extending in a direction substantially parallel to the flow path for the first working fluid through the tubes. The fold can define first and second legs of the insert. A dimple can be formed on the first leg and a protrusion can be formed on the second leg opposite to the dimple on the first leg.