RQL Combustor Nozzle Layout for Lower nvPM Aviation Fuel Burn
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Solution Overview
Problem
Gas turbine engines emit varying levels of non-volatile particulate matter (nvPM) depending on the fuel type and operating parameters, necessitating adjustments in operating methods to reduce emissions.
Innovation Solution
Implementing a gas turbine engine with a rich burn, quick quench, lean burn (RQL) combustor and optimizing fuel distribution, ignition, and combustion using sustainable aviation fuel (SAF) to achieve specific nvPM emissions index ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If traditional kerosene-based jet fuels are used in gas turbine engines, then the engine operates with established fuel compatibility and combustion efficiency, but non-volatile particulate matter (nvPM) emissions increase and soot deposits form within the engine and downstream components
Solution Approach 1:
The patent modifies combustion parameters by implementing a three-stage burn process (rich burn, quick quench, lean burn) with specific fuel injection timing and air-fuel ratio control. The rich burn stage uses high fuel concentration for rapid ignition, followed by quick quenching with air to suppress soot formation, then lean burn to complete combustion. This parameter optimization reduces nvPM emissions while maintaining reliable combustion of sustainable aviation fuels
Solution Approach 2:
The combustor operates in a periodic cycle through the rich burn-quick quench-lean burn sequence. Fuel is injected in controlled pulses rather than continuously, with each pulse followed by an air quench period. This periodic action allows the combustion process to reset and prevents accumulation of soot and particulate matter, reducing nvPM emissions while maintaining stable combustion
2Object-generated harmful factors
If sustainable aviation fuel (SAF) is used to reduce carbon emissions, then environmental impact decreases, but nvPM emissions and soot deposits increase compared to traditional fuels
Solution Approach 1:
The patent optimizes combustion parameters specifically for SAF by implementing variable air-fuel ratios and controlled fuel injection timing. The rich burn phase provides sufficient oxygen to prevent soot formation, the quick quench phase suppresses particulate matter, and the lean burn phase ensures complete combustion. This parameter optimization reduces nvPM emissions from SAF while maintaining the environmental benefits of using sustainable fuels
Solution Approach 2:
The patent converts the inherent soot-forming tendency of SAF into a benefit by using the rich burn-quick quench-lean burn process. The initial rich burn creates controlled soot formation that is then rapidly oxidized during the lean burn phase, transforming the harmful soot production into a controlled combustion process that ultimately reduces nvPM emissions while maintaining SAF's environmental advantages
3Productivity
If fuel spray nozzles are increased in number to improve fuel distribution, then combustion efficiency improves, but device complexity increases
Solution Approach 1:
The combustor is segmented into three distinct functional zones: rich burn zone, quick quench zone, and lean burn zone. Each zone has specific fuel spray nozzle configurations optimized for its particular combustion requirements. This segmentation allows independent optimization of each zone's fuel distribution while maintaining overall system manageability, improving combustion efficiency without excessive complexity
Solution Approach 2:
Different regions of the combustor have different fuel spray nozzle configurations and air-fuel ratio characteristics tailored to local combustion requirements. The rich burn zone has higher fuel concentration, the quick quench zone has higher air flow, and the lean burn zone has optimized mixture ratios. This local quality optimization improves overall combustion efficiency while keeping each local region's design relatively simple
4Object-generated harmful factors
If operating parameters are adjusted to reduce nvPM emissions, then air quality improves, but engine performance and thrust may be affected
Solution Approach 1:
The rich burn-quick quench-lean burn process ensures continuous and complete combustion throughout the combustion cycle. The rich burn provides rapid ignition and heat release, the quick quench suppresses soot without stopping combustion, and the lean burn completes the oxidation process. This continuous combustion action maintains engine thrust while progressively reducing nvPM emissions through the three-stage process
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
Reduces non-volatile particulate matter emissions, minimizing soot deposits and contrail formation, improving local air quality, and reducing environmental impact.
Implementation Method 1
a rich burn, quick quench, lean burn (RQL) combustor having a number of fuel spray nozzles
Implementation Method 2
The inventors have identified that the emissions of a gas turbine engine are sensitive to the fuel being used
Implementation Method 3
a rich burn, quick quench, lean burn (RQL) combustor
Implementation Method 4
reduced nvPM in the exhaust may lead to reduced contrail strength and/or time taken for a contrail to disperse
Data Source
AI summary
A gas turbine engine includes: a rich burn, quick quench, lean burn combustor having a number of fuel spray nozzles in range of 14-22 or a number of fuel spray nozzles per unit engine core size in range 2 to 6. An MTO nvPM emissions index ratio is:EImaxTO,SAFEImaxTO,FF×Wf,maxTOwhere: EImaxTO,SAF and EImaxTO,FF are respectively the nvPM emissions index in mg/kg when operating around 100% available thrust for given operating conditions if fuel provided to fuel spray nozzles includes either sustainable aviation fuel (SAF) or fossil-based hydrocarbon fuel; Wf,maxTO is mass flow rate of fuel provided to fuel spray nozzles in kg/s when gas turbine engine is operating at around 100% available thrust for given operating conditions. MTO nvPM emissions index is less than 2. The gas turbine engine is configured to provide fuel including SAF to fuel spray nozzles. Also disclosed is method of operating gas turbine engine.