Additive Manufacturing Mixing Element for Burner Flashback Protection

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Solution Overview

Problem

Burners of the second category face a trade-off between safety from flame flashbacks and optimal combustion homogeneity, with existing designs not achieving complete combustion and increasing nitrogen oxide formation.

Innovation Solution

An additive manufacturing process is used to create a mixing element with branching intermediate channels that supply oxidizing agent and fuel separately and homogeneously into the combustion chamber, incorporating features like helical grooves and swirl elements to enhance mixing, and exhaust gas recirculation to reduce nitrogen oxide formation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If separate feed lines for oxidizer and fuel are used (second category burner), then flashback protection is improved, but mixture homogeneity deteriorates

Engineering Contradiction:
Improveflashback protectionVSAvoidmixture homogeneity
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The mixing element is divided into multiple separate channels (first channel for oxidizer, second channel for fuel) that maintain separation until the combustion chamber, preventing flashback while enabling controlled mixing. The channels are segmented into distinct pathways that only converge at the combustion zone.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the mixing element have different functions: the channels maintain separation for safety, while the combustion chamber provides the localized mixing zone. The mixing element structure varies locally to achieve separation in channels and mixing in the combustion chamber.

Inventive Principle:
Principle #3Local quality

2Stability of the object's composition

If premix injection is used (first category burner), then mixture homogeneity is improved, but flashback protection deteriorates

Engineering Contradiction:
Improvemixture homogeneityVSAvoidflashback protection
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The system segments the oxidizer and fuel supply paths into separate channels until the combustion chamber, preventing premature mixing that could cause flashback while still achieving homogeneity in the controlled combustion zone.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The mixing element acts as an intermediary structure that maintains separation of oxidizer and fuel through its channels while providing a controlled interface (combustion chamber) where mixing occurs safely without flashback.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of manufacture

If conventional manufacturing is used for mixing element, then manufacturing simplicity is improved, but combustion optimization deteriorates

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidcombustion efficiency
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The additive manufacturing process enables complex channel geometries, helical grooves, and swirl elements that cannot be achieved with conventional manufacturing. These geometric parameters are optimized to enhance mixing and combustion efficiency.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The mixing element incorporates multiple functional features (channels, helical grooves, swirl elements) into a single integrated component manufactured additively, combining structural and flow-control functions that would require multiple parts with conventional manufacturing.

Inventive Principle:
Principle #40Composite 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

This design ensures a homogeneous fuel-oxidizer mixture across the burner's performance range, reducing nitrogen oxide formation and increasing efficiency, thereby achieving complete combustion and lowering fuel costs.

Implementation Method 1

the mixing element (5) is manufactured using an additive manufacturing process

Methodology Applied
Scientific EffectAdditive manufacturing: 3D Printing

Implementation Method 2

incorporating features like helical grooves and swirl elements to enhance mixing

Methodology Applied
Scientific EffectSwirl flow: Vortex Ring

Implementation Method 3

The burner design, particularly the combustion chamber, and the supply of the oxidizer and fuel have a considerable influence on NOx formation during combustion. An additively manufactured mixing element can be optimized to either completely suppress or minimize the formation of such NOx. One possibility is for the burner to incorporate exhaust gas recirculation

Methodology Applied
Scientific EffectExhaust gas recirculation: Convection

Implementation Method 4

at least one oxidizing agent, preferably air or oxygen, is combusted with a fuel in the combustion chamber in a continuous reaction, releasing heat

Methodology Applied
Scientific EffectCombustion: Combustion

Data Source

PatentEP3655701B1Burner
Publication Date: 2024.09.18 KUEPPERS SOLUTIONS GMBH
  • EP3655701B1 patent drawingFigure 1~2
  • EP3655701B1 patent drawingFigure 3~4
  • EP3655701B1 patent drawingFigure 5~6

AI summary

A burner (1) having a housing (2) on which a combustion tube (3) is arranged, wherein the combustion tube (3) has an opening (4) at the end averted from the housing (2), wherein a mixing element (5) is provided in the combustion tube (3), and the space between said mixing element (5) and the opening (4) forms a combustion chamber (6), wherein the housing (2) has at least two mutually separate channels (8) which open out in the mixing element (5), wherein gases flow through the channels (8) and the mixing element (5), and mixing of said gases takes place for the first time in a combustion chamber (6), wherein the mixing element (5) is produced in an additive manufacturing process and has at least two separate intermediate channels (9) which branch in the direction of the combustion chamber (6) in a flow direction.