Lean-Burn RQL Combustor Nozzle Count for SAF nvPM Reduction
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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 gas turbine engine incorporates a rich burn, quick quench, lean burn (RQL) combustor with specific fuel spray nozzle configurations and provides fuel injection methods to optimize the distribution, ignition, and combustion of sustainable aviation fuel, defining various emissions index ratios to minimize nvPM emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the number of fuel spray nozzles is increased to improve fuel distribution and combustion efficiency, then combustion efficiency is improved, but device complexity increases
Solution Approach 1:
The patent optimizes the number of fuel spray nozzles to a specific range (14-22 nozzles) rather than simply increasing them indefinitely. This parameter optimization achieves sufficient fuel distribution and combustion efficiency while avoiding excessive device complexity. The specific nozzle count represents a balanced parameter choice that satisfies combustion requirements without over-engineering the system.
2Object-generated harmful factors
If fuel injection methods are optimized to reduce nvPM emissions, then environmental impact is reduced, but device complexity increases
Solution Approach 1:
The patent employs parameter optimization in the fuel injection system, specifically controlling the number of nozzles within 14-22 and optimizing their distribution pattern. This approach reduces nvPM emissions by achieving better fuel-air mixing and more complete combustion, while avoiding the need for overly complex injection systems. The solution lies in optimizing existing parameters rather than adding complex control mechanisms.
3Object-generated harmful factors
If the combustor is designed for complete combustion to reduce emissions, then emission levels are reduced, but energy efficiency may deteriorate due to increased heat loss
Solution Approach 1:
The patent implements local quality optimization within the combustor by strategically distributing 14-22 fuel spray nozzles throughout the combustion chamber. This creates localized zones of optimized fuel-air mixing and combustion, ensuring complete combustion in critical areas while maintaining overall energy efficiency. The non-uniform distribution of nozzles allows different regions of the combustor to have tailored combustion characteristics that balance emission reduction with energy conservation.
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, leading to decreased soot deposits, improved air quality, and reduced contrail formation, particularly at idle and cruise conditions, thereby minimizing environmental impact.
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
rich burn, quick quench, lean burn (RQL) combustor
Data Source
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AI summary
A gas turbine engine (10) for an aircraft. The gas turbine engine (10) comprising: a rich burn, quick quench, lean burn (RQL) combustor (16) having a number of fuel spray nozzles (403, 404) in the range of 14-22 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 ratio is defined as: EIidleEImaxTO 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; and 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. The first idle-MTO nvPM emissions index ratio of the gas turbine engine (10) is less than 0.8. The gas turbine engine (10) is configured to provide fuel comprising a sustainable aviation fuel (SAF) to the fuel spray nozzles (403, 404). A method of operating the gas turbine engine is also disclosed.