Dual-Fuel Injector Assembly for Low-Emission Aircraft Combustion

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Solution Overview

Problem

Existing injector arrangements for aircraft engines fail to achieve low-emission combustion using gaseous and liquid fuels efficiently, particularly when introducing hydrogen and kerosene or sustainable alternative fuels, due to inadequate fuel mixing and potential flame flashback issues.

Innovation Solution

The injector arrangement features a centrally designed gas channel for gaseous fuel introduction, surrounded by an air channel for premixing, with separate supply lines for gaseous and liquid fuels, and additional air channels for swirl generation and recirculation, optimizing flow patterns for low-emission combustion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If a central air channel with radial gas fuel injection is used, then fuel mixing is improved, but flame flashback risk increases

Engineering Contradiction:
Improvefuel mixingVSAvoidflame flashback risk
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The injection system is segmented into separate functional channels: a central gas fuel channel (first gas channel) surrounded by an air channel (second gas channel). This segmentation allows independent control of fuel and air flows, enabling premixing while maintaining flow direction control to prevent flashback into the fuel supply line.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The air channel acts as an intermediary between the gas fuel channel and the combustion chamber. Gas fuel is introduced into the air channel where it mixes with air before reaching the combustion chamber, preventing direct exposure of the fuel supply to flame while achieving thorough mixing.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If gaseous fuel is introduced directly into the combustion chamber, then injection complexity is reduced, but emission control deteriorates

Engineering Contradiction:
Improveinjection complexityVSAvoidemission control
Core Design Contradiction:
Device complexityVSObject-generated harmful factors

Solution Approach 1:

Premixing of gaseous fuel with air is performed in advance within the air channel before the mixture enters the combustion chamber. This preliminary mixing action enables low-emission combustion by ensuring proper fuel-air ratio is achieved before combustion, while adding only minimal structural complexity.

Inventive Principle:
Principle #10Preliminary action

3Productivity

If multiple fuel injection points are provided, then combustion efficiency is improved, but device complexity increases

Engineering Contradiction:
Improvecombustion efficiencyVSAvoiddevice complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

Multiple fuel types (gaseous fuel and liquid fuel) are merged into a single injector assembly with integrated supply lines and injection points. The gaseous fuel supplies the central channel while liquid fuel supplies the surrounding annular channel, combining multiple functions in one compact device that maintains high combustion efficiency.

Inventive Principle:
Principle #5Merging (Combining)

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 solution enables low-emission combustion with reduced thermal stress on the injector, stabilized combustion zones, and efficient mixing of hydrogen and kerosene or sustainable fuels, minimizing nitrogen oxide emissions.

Implementation Method 1

a first gas channel (12) arranged centrally on a longitudinal axis (L) of the injector with a downstream outlet opening (14) for introducing a gas flow

Methodology Applied
Scientific EffectGas flow through channel:

Implementation Method 2

the gaseous fuel is first introduced axially into a further channel, in particular an air channel surrounding the first gas channel, and is at least partially premixed with the (gas, especially air) flow through the further channel

Methodology Applied
Scientific EffectTurbulent mixing: Turbulence

Implementation Method 3

a liquid fuel injection arranged radially around the first gas channel for introducing the liquid fuel into the combustion chamber

Methodology Applied
Scientific EffectLiquid fuel injection: Injector

Implementation Method 4

for introducing a gaseous fuel and a liquid fuel as well as air into a combustion chamber

Methodology Applied
Scientific EffectCombustion: Combustion

Data Source

PatentEP4664010A1Injector assembly for an engine and aircraft
Publication Date: 2025.12.17 ROLLS ROYCE DEUT LTD & CO KG
  • EP4664010A1 patent drawingFigure 1
  • EP4664010A1 patent drawingFigure 2
  • EP4664010A1 patent drawingFigure 3

AI summary

The invention relates to an injector arrangement (1) for a gas turbine, in particular an aircraft engine, for introducing a gaseous fuel and a liquid fuel as well as air into a combustion chamber (CC), comprising an injector shaft (2) and an injector main body (3) aligned along an injector longitudinal axis (L), wherein the injector main body (3) comprises: - a first gas channel (12) arranged centrally on the injector longitudinal axis (L) with a downstream outlet opening (14) for introducing a gas flow, - at least one air channel (31, 36, 40) arranged radially around the outside of the first gas channel (12), as a second gas channel (30), and - a liquid fuel injection (24) arranged radially around the first gas channel (12) for introducing the liquid fuel into the combustion chamber (CC).An advantageous emission characteristic can be achieved by designing the first gas channel (12) exclusively for introducing the gaseous fuel into the combustion chamber (CC) (Fig. 1).