Additive Manufactured Heat Exchanger Tubes with Varying Cross-Sections

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Solution Overview

Problem

Conventional heat exchangers in motor vehicles face efficiency reduction due to constant tubular cross-sections, leading to decreased gas velocity and heat transfer coefficients as gases cool, resulting in undesirable performance.

Innovation Solution

The use of tubular bodies with varying cross-sections produced through additive manufacturing, such as laser melting, ensures constant gas velocity and improved heat transfer efficiency by adapting to local flow conditions, eliminating the need for complex fastening and reducing pressure losses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a constant tubular cross-section is used in conventional heat exchangers, then the structure is simple to manufacture, but the gas velocity decreases and heat transfer efficiency is reduced as gases cool

Engineering Contradiction:
Improvestructural simplicityVSAvoidheat transfer efficiency
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The patent applies parameter changes by varying the tubular cross-section dimensions along the direction of extension. The tubular bodies transition from larger cross-sections at the inlet to smaller cross-sections at the outlet, dynamically adjusting flow parameters to maintain constant gas velocity and heat transfer coefficient throughout the heat exchanger, thereby resolving the contradiction between manufacturing simplicity and heat transfer efficiency

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements local quality by creating non-uniform tubular cross-sections where different sections have different dimensions tailored to local flow conditions. The inlet sections have larger cross-sections to accommodate higher volume flow, while outlet sections have smaller cross-sections to maintain velocity as gas density increases, optimizing heat transfer efficiency at each location rather than using a uniform structure

Inventive Principle:
Principle #3Local quality

2Productivity

If the tubular cross-section is reduced to maintain constant gas velocity, then heat transfer efficiency is improved, but pressure losses increase

Engineering Contradiction:
Improveheat transfer efficiencyVSAvoidpressure losses
Core Design Contradiction:
ProductivityVSLoss of energy

Solution Approach 1:

The patent uses parameter changes to gradually reduce the tubular cross-section along the flow direction, allowing the gas to cool and densify while maintaining constant velocity. This gradual transition minimizes sudden pressure drops that would occur with abrupt cross-section changes, thereby achieving improved heat transfer efficiency while controlling pressure losses through optimized geometric progression

Inventive Principle:
Principle #35Parameter changes

3Productivity

If additive manufacturing is used to produce tubular bodies with varying cross-sections, then heat transfer efficiency is improved, but manufacturing complexity increases

Engineering Contradiction:
Improveheat transfer efficiencyVSAvoidmanufacturing process complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent replaces traditional mechanical manufacturing methods (such as machining or assembling multiple components) with additive manufacturing technology. This substitution enables the direct fabrication of complex tubular bodies with continuously varying cross-sections in a single process, eliminating the need for complex tooling, multiple assembly steps, or conventional machining operations, thereby making the complex geometry manufacturable

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 approach enhances the efficiency of heat exchangers by maintaining constant gas velocity and heat transfer coefficients, reducing pressure losses, and allowing for a more compact design with cost savings.

Implementation Method 1

the tubular bodies are produced according to the invention by means of an additive manufacturing process

Methodology Applied
Scientific EffectAdditive manufacturing: 3D Printing

Implementation Method 2

the fresh air to be cooled is introduced into the heat exchanger, where it thermally interacts with a coolant that is also introduced into the heat exchanger and in this way can give off heat to the coolant

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 3

The additive manufacturing process can preferably include laser melting

Methodology Applied
Scientific EffectLaser melting: Laser Beam Welding

Data Source

PatentEP3265738B1Heat exchanger, in particular for a motor vehicle
Publication Date: 2018.12.12 MAHLE INT GMBH
  • EP3265738B1 patent drawingFigure 1
  • EP3265738B1 patent drawingFigure 2~3
  • EP3265738B1 patent drawingFigure 4~5

AI summary

The invention relates to a heat exchanger (1), in particular for a motor vehicle, comprising - a plurality of first fluid paths (2a) for a first fluid (F1) to flow through and a plurality of second fluid paths (2b) for a second fluid (F2) to flow through, said second fluid paths being fluidically separate from but thermally connected to the first fluid paths (2a), wherein - the fluid paths (2a, 2b) are delimited by tube elements (3) which are produced by means of an additive production method, - a tube cross-section (q), which is measured perpendicularly to the direction of extension (R), of at least one tube element (3), preferably a plurality of the tube elements (3), most preferably all of the tube elements (3), increases or decreases at least in some sections along the direction of extension (R).