Fuel Nozzle Grouping in Aircraft Combustors for Lower nvPM
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Solution Overview
Problem
Gas turbine engines emit varying amounts of non-volatile particulate matter (nvPM) depending on the fuel type and operating parameters, necessitating adjustments in operating methods to reduce emissions.
Innovation Solution
The gas turbine engine incorporates a system where a plurality of fuel spray nozzles are configured to inject fuel at different flow rates, with a specific ratio, and operates using sustainable aviation fuel (SAF) to achieve reduced nvPM emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If traditional kerosene-based jet fuel is used in gas turbine engines, then the engine can operate with established fuel infrastructure, but nvPM emissions increase and environmental impact worsens
Solution Approach 1:
The patent changes the chemical composition parameter of the fuel by introducing sustainable aviation fuel (SAF) with different molecular structures and properties compared to traditional kerosene. This parameter change reduces nvPM emissions while maintaining engine compatibility, as SAF burns cleaner with lower particulate formation potential.
Solution Approach 2:
The patent employs composite fuel formulations that combine SAF with traditional jet fuel in various blends. This composite approach allows the system to benefit from the lower emissions of SAF while maintaining compatibility with existing engine designs and fuel infrastructure, gradually transitioning away from pure kerosene-based fuels.
2Object-affected harmful factors
If fuel composition is changed to reduce nvPM emissions, then environmental impact improves, but engine performance and thrust efficiency may deteriorate
Solution Approach 1:
The patent optimizes combustion parameters including temperature, pressure, and residence time to accommodate SAF's different combustion characteristics. By adjusting these parameters, the engine maintains thrust efficiency while leveraging SAF's lower nvPM formation potential, resolving the trade-off between emissions and performance.
Solution Approach 2:
The patent implements dynamic fuel injection control that adapts injection timing, duration, and pressure based on operating conditions and fuel type. This dynamic adjustment ensures optimal combustion efficiency and thrust output when using SAF, preventing performance deterioration despite the fuel composition change.
3Productivity
If fuel spray nozzles are configured with different flow rates, then fuel distribution and combustion efficiency improve, but device complexity increases
Solution Approach 1:
The patent divides the fuel injection system into multiple nozzle groups with different flow rate characteristics. Each nozzle group is optimized for specific combustion zones, allowing differentiated fuel delivery that improves combustion efficiency and nvPM reduction while maintaining manageable system complexity through modular segmentation.
Solution Approach 2:
The patent applies local quality by assigning different flow rates to nozzles in different spatial locations within the combustor. Nozzles in regions requiring richer mixtures receive higher flow rates, while others receive lower rates, optimizing combustion in each local zone and improving overall efficiency without requiring complete system redesign.
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 and use of sustainable aviation fuels (SAF) reduce the nvPM emissions and improve the thrust efficiency and environmental impact, thereby reducing soot deposits within the engine and improving local air quality.
Implementation Method 1
a plurality of fuel spray nozzles configured to inject fuel into the combustion chamber
Implementation Method 2
a combustor, comprising a combustion chamber and a plurality of fuel spray nozzles configured to inject fuel into the combustion chamber
Data Source
Figure 1
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AI summary
A gas turbine engine (10) for an aircraft is disclosed. The gas turbine engine (10) comprises: 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 1:3 to 1:6. A fuel-flow nvPM emissions index ratio is defined as: EIidle×Wf,idleEImaxTO×Wf,maxTO where: EIidle is the system loss corrected nvPM emissions index in mg/kg of the gas turbine engine (10) if operating at around 7% available thrust for given operating conditions; EImaxTO is the system loss corrected nvPM emissions index in mg/kg of the gas turbine engine (10) if operating at around 100% available thrust for the given operating conditions; Wf,idle is the rate of fuel flow to the fuel spray nozzles in kg/s at around 7% available thrust for the given operating conditions; and Wf,maxTO is the rate of fuel flow to the fuel spray nozzles in kg/s at around 100% available thrust for the given operating conditions. The fuel-flow nvPM emissions index ratio of the gas turbine engine (10) is less than 0.3. The gas turbine engine (10) is configured to provide fuel comprising a sustainable aviation fuel (SAF) to the plurality of fuel spray nozzles (124). Also disclosed are methods of operating a gas turbine engine.