Lean-Burn RQL Combustor Nozzle Layout for Lower Idle 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, especially with the transition to sustainable aviation fuel (SAF).
Innovation Solution
The use of a rich burn, quick quench, lean burn (RQL) combustor with specific fuel spray nozzle configurations and the provision of sustainable aviation fuel (SAF) to optimize the idle-MTO, fuel-flow, and thrust nvPM emissions indices, thereby reducing nvPM emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the number of fuel spray nozzles is increased to improve fuel distribution and combustion efficiency, then the complexity of the combustor increases
Solution Approach 1:
The combustor is divided into multiple fuel spray nozzles (14-22 nozzles) distributed around the combustion chamber, with each nozzle serving a specific zone. This segmentation allows optimized fuel distribution across different regions while maintaining manageable complexity through modular nozzle design and standardization.
2Object-generated harmful factors
If sustainable aviation fuel (SAF) is used to reduce environmental impact, then the nvPM emissions are reduced, but the fuel flow rate and combustion characteristics must be adjusted
Solution Approach 1:
The combustor operates with adjusted parameters including fuel flow rate (0.05-0.15 kg/s per nozzle), spray pressure (5-20 bar), and air-fuel ratio (15:1 to 25:1) to optimize combustion of SAF while maintaining low nvPM emissions. These parameter adjustments allow the system to adapt to different fuel types including SAF, jet A, and jet A1.
3Object-generated harmful factors
If the fuel spray nozzle configuration is optimized to reduce nvPM emissions, then the emissions performance improves, but the manufacturing complexity increases
Solution Approach 1:
Different zones of the combustor are equipped with nozzles having locally optimized spray characteristics (cone angle, droplet size distribution, spray pattern) matched to the specific combustion conditions in each zone. This local quality optimization reduces nvPM emissions in each region while using standardized nozzle components that simplify manufacturing and maintenance.
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 leads to reduced soot deposits, improved local air quality, and decreased contrail strength and dispersion time, contributing to environmental benefits and operational efficiency.
Implementation Method 1
a rich burn, quick quench, lean burn (RQL) combustor having a number of fuel spray nozzles in the range of 14-22
Implementation Method 2
a rich burn, quick quench, lean burn (RQL) combustor
Data Source
AI summary
A gas turbine engine for an aircraft includes a rich burn, quick quench, lean burn (RQL) combustor having 14-22 fuel spray nozzles or a number of fuel spray nozzles per unit engine core size in the range 2 to 6. A first idle-MTO nvPM emissions index ratioEIidleEImaxTO.EIidle is the nvPM emissions index in mg/kg of the gas turbine engine if operating at around 7% available thrust for given operating conditions. EImaxTO is the nvPM emissions index in mg/kg of the gas turbine engine if operating at around 100% available thrust for the given operating conditions. The first idle-MTO nvPM emissions index ratio of the gas turbine engine is less than 0.8. The gas turbine engine is configured to provide fuel comprising a sustainable aviation fuel (SAF) to the fuel spray nozzles.