Lean-Burn Combustor Nozzle Sizing 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 effectively.
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 fuel distribution, ignition, and combustion, thereby defining and maintaining low nvPM emissions indices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If traditional kerosene-based jet fuel is used in gas turbine engines, then the engine operates with established performance characteristics, but non-volatile particulate matter (nvPM) emissions increase
Solution Approach 1:
The patent changes the chemical composition parameters of the fuel by using sustainable aviation fuel (SAF) with different properties compared to traditional kerosene. This parameter change in fuel composition directly reduces nvPM emissions while maintaining engine performance and fuel consumption characteristics
Solution Approach 2:
The patent employs a Rich Burn Quick Quench Lean Burn (RBQQL) combustor configuration that uses a specific sequence of fuel injection and combustion zones. This temporary rich burn phase followed by quick quenching creates conditions that reduce nvPM formation without requiring permanent structural changes to the engine, effectively using a transient combustion mode to achieve emission reduction
2Productivity
If the number of fuel spray nozzles is increased to improve fuel distribution, then combustion efficiency improves, but device complexity increases
Solution Approach 1:
The patent segments the combustion process into distinct zones: a rich burn zone, a quick quench zone, and a lean burn zone. This segmentation allows each zone to perform its specific function optimally, achieving high combustion efficiency through controlled fuel distribution rather than simply increasing the number of nozzles
Solution Approach 2:
The patent uses variable fuel injection timing and zone control where the rich burn, quick quench, and lean burn phases are dynamically sequenced. This dynamic control of combustion zones achieves superior combustion efficiency and emission reduction without requiring a proportional increase in nozzle quantity, as the system adapts the combustion process rather than relying on static nozzle multiplication
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, and reduces the environmental impact of contrails.
Implementation Method 1
a number of fuel spray nozzles in the range of 14-22
Implementation Method 2
fuel spray nozzles per unit engine core size
Implementation Method 3
a rich burn, quick quench, lean burn (RQL) combustor
Implementation Method 4
rich burn, quick quench, lean burn (RQL) combustor
Implementation Method 5
rich burn, quick quench, lean burn (RQL) combustor
Data Source
AI summary
A gas turbine engine for an aircraft. The gas turbine engine comprising: a rich burn, quick quench, lean burn (RQL) combustor having a number of fuel spray nozzles 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:EIidle/EImaxTO where: EIidle is the system loss corrected nvPM emissions index in mg/kg of the gas turbine engine 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 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. A method of operating the gas turbine engine is also disclosed.