SAF Combustor Nozzle Staging for Lower Aircraft nvPM Emissions

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Solution Overview

Problem

The emissions of non-volatile particulate matter from gas turbine engines, specifically gas turbine engines, specifically gas turbine engines, specifically gas turbine engines, specifically gas turbine engines, specifically gas turbine engines, specifically non-volatile particulate matter from gas turbine engines, specifically gas turbine engines, are sensitive to the fuel type and operating parameters, leading to varying levels of non-volatile particulate matter (nvPM) emissions, which impact environmental and operational factors.

Innovation Solution

The implementation of a gas turbine engine configured to operate using sustainable aviation fuel (SAF) and employing a combustor with a plurality of fuel spray nozzles, where a subset of nozzles receives a higher fuel flow rate, optimizing the distribution and combustion of SAF to reduce nvPM emissions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-generated harmful factors

If traditional kerosene-based jet fuels are used, then fuel availability and energy density are maintained, but non-volatile particulate matter (nvPM) emissions increase

Engineering Contradiction:
ImprovenvPM emissionsVSAvoidfuel type flexibility
Core Design Contradiction:
Object-generated harmful factorsVSAdaptability or versatility

Solution Approach 1:

The patent modifies operating parameters (fuel flow rates per nozzle, combustor conditions) to optimize nvPM emissions when using SAF. By adjusting these parameters, the system achieves lower emissions while maintaining the ability to operate with different fuel types.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system dynamically adjusts fuel distribution across multiple nozzles based on operating conditions. The variable fuel flow rates and dynamic combustor control enable the engine to adapt to different fuel types (SAF, kerosene) while optimizing emissions performance.

Inventive Principle:
Principle #15Dynamics

2Power

If fuel flow rate is increased to maintain thrust, then power output is maintained, but nvPM emissions increase

Engineering Contradiction:
Improvethrust outputVSAvoidnvPM emissions
Core Design Contradiction:
PowerVSObject-generated harmful factors

Solution Approach 1:

The fuel injection system is divided into multiple nozzles with different fuel flow rates. This segmentation allows optimized combustion across different zones, maintaining thrust while reducing peak nvPM emissions by distributing fuel flow strategically rather than using uniform high flow rates.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different nozzles receive different fuel flow rates tailored to local combustion requirements. This creates localized optimal combustion conditions that balance power output with reduced nvPM emissions, avoiding uniform high-emission operation.

Inventive Principle:
Principle #3Local quality

3Object-generated harmful factors

If SAF is used to reduce emissions, then environmental impact is reduced, but combustion stability and efficiency may be affected

Engineering Contradiction:
ImprovenvPM emissionsVSAvoidcombustion stability
Core Design Contradiction:
Object-generated harmful factorsVSReliability

Solution Approach 1:

The system incorporates sensors and control mechanisms that monitor combustion conditions and adjust fuel flow rates accordingly. This feedback ensures combustion stability when using SAF by real-time optimization of burning conditions, preventing instability while maintaining low emissions.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

Dynamic adjustment of fuel flow rates and combustor parameters enables the system to adapt to SAF combustion characteristics. This dynamic control maintains combustion stability and efficiency while achieving reduced nvPM emissions compared to static operation.

Inventive Principle:
Principle #15Dynamics

4Object-generated harmful factors

If multiple fuel spray nozzles are used with different fuel flow rates, then nvPM emissions are reduced, but device complexity increases

Engineering Contradiction:
ImprovenvPM emissionsVSAvoidfuel spray nozzle configuration
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The fuel injection system is segmented into multiple nozzles with differentiated fuel flow rates. This segmentation, while increasing component count, enables superior emission control through optimized local combustion, achieving the trade-off between complexity and environmental performance.

Inventive Principle:
Principle #1Segmentation

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 reduces nvPM emissions, minimizing soot deposits, contrail formation, and improving local air quality, particularly at idle and cruise conditions, thereby reducing environmental impact and enhancing operational efficiency.

Implementation Method 1

a combustor, comprising a combustion chamber and a plurality of fuel spray nozzles configured to inject fuel into the combustion chamber

Methodology Applied
Scientific EffectCombustion: Combustion

Data Source

PatentEP4663923A1Aircraft emissions
Publication Date: 2025.12.17 ROLLS ROYCE PLC
  • EP4663923A1 patent drawingFigure 1~2
  • EP4663923A1 patent drawingFigure 3~4
  • EP4663923A1 patent drawingFigure 5

AI summary

A gas turbine engine for an aircraft. The gas turbine engine comprising: a combustor (16), comprising a combustion chamber (120) and a plurality of fuel spray nozzles (124) configured to inject fuel into the combustion chamber (120), wherein the plurality of fuel spray nozzles (124) comprises a first subset (124A) of fuel spray nozzles (124) and a second subset (124B) of fuel spray nozzles (124), wherein the combustor (16) is operable in a condition in which each of the fuel spray nozzles of the first subset (124A) of fuel spray nozzles (124) is supplied with fuel at a greater fuel flow rate than each of the fuel spray nozzles of the second subset (124B) of fuel spray nozzles (124), wherein a ratio of the number of fuel spray nozzles (124) in the first subset (124A) of fuel spray nozzles (124) to the number of fuel spray nozzles (124) in the second subset (124B) of fuel spray nozzles (124) is in the range of 1:2 to 1:5. An MTO nvPM emissions index ratio-modified fuel flow is defined as: EImaxTO,SAFEImaxTO,FF×Wf,maxTO where: EImaxTO,SAF is the system loss corrected nvPM emissions index in mg/kg of the gas turbine engine (10) when operating at around 100% available thrust for given operating conditions if a fuel provided to the plurality of fuel spray nozzles (124) comprises a sustainable aviation fuel (SAF); EImaxTO,FF is the system loss corrected nvPM emissions index in mg/kg of the gas turbine engine (10) when operating at around 100% available thrust for the given operating conditions if a fuel provided to the plurality of fuel spray nozzles (124) is a fossil-based hydrocarbon fuel; and Wf,maxTO is the mass flow rate of fuel provided to the plurality of fuel spray nozzles (124) in kg/s when the gas turbine engine (10) is operating at around 100% available thrust for the given operating conditions. The MTO nvPM emissions index ratio-modified fuel flow of the gas turbine engine (10) in kg/s is less than 2. The gas turbine engine (10) is configured to provide fuel comprising a SAF to the plurality of fuel spray nozzles (124). Also disclosed is a method of operating the gas turbine engine.