Aircraft Combustor Nozzle Split for Lower SAF nvPM Emissions
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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 is configured with a combustor featuring distinct subsets of fuel spray nozzles, optimized for fuel distribution and combustion of sustainable aviation fuel (SAF), with specific ratios and flow rates to achieve reduced nvPM emissions indices at different operational conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If traditional kerosene-based jet fuel is used, then the engine operates with established performance characteristics, but nvPM emissions are higher compared to SAF
Solution Approach 1:
The patent applies parameter changes by adjusting operating parameters (fuel flow rate, air flow rate, combustor temperature, equivalence ratio) when transitioning between different fuel types (SAF vs. kerosene). This allows the engine to optimize combustion characteristics for each fuel type, thereby reducing nvPM emissions when using SAF while maintaining fuel versatility.
2Object-generated harmful factors
If operating parameters are adjusted to reduce nvPM emissions, then environmental impact is reduced, but engine performance may be compromised
Solution Approach 1:
The patent employs dynamic adjustment of operating parameters based on fuel type and flight conditions. The control system continuously monitors and adjusts fuel flow rate, air flow rate, and combustor temperature to maintain optimal thrust while minimizing nvPM emissions. This dynamic approach allows the engine to achieve both performance and emission reduction goals simultaneously.
Solution Approach 2:
The patent changes operating parameters (equivalence ratio, fuel flow rate, air flow rate, combustor temperature) to reduce nvPM emissions while maintaining engine power. By optimizing these parameters specifically for SAF combustion, the engine achieves lower emissions without sacrificing thrust performance.
3Productivity
If fuel flow rate to individual nozzles is increased, then combustion efficiency improves, but nvPM emissions increase
Solution Approach 1:
The patent applies local quality by distributing fuel flow non-uniformly across different nozzle groups. Specifically, nozzles in the first group receive a higher fuel flow rate than nozzles in the second group. This localized differentiation optimizes combustion efficiency in regions where it is most needed while controlling nvPM emissions in other regions, achieving an overall balance between productivity and emission reduction.
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 minimized contrail formation and dispersion, contributing to environmental benefits and operational efficiency.
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
AI summary
An aircraft gas turbine engine includes a combustor, with a combustion chamber and fuel spray nozzles to inject fuel into the chamber. The nozzles include first and second subsets. The first subset of nozzles is supplied with fuel at a greater rate than each of the second subset. A ratio of nozzles in the first subset to the second subset is 1:3 to 1:6. A lean cruise nvPM emissions index ratio isEIcruise(lean),SAFEIcruise(lean),FF,where EIcruise(lean),SAF isEImaxTO,SAF+EIclimb,SAF2and EIcruise(lean),FF isEImaxTO,FF+EIclimb,FF2.EImaxTO,SAF is nvPM emissions index operating at 100% available thrust and EIclimb,SAF is the nvPM emissions index operating at 85% available thrust if fuel includes sustainable aviation fuel. EImaxTO,FF is the nvPM emissions index operating at 100% available thrust and EIclimb,FF is the nvPM emissions index at 85% available thrust if fuel is a fossil-based hydrocarbon. The lean cruise nvPM emissions index ratio is less than 1.