Combustor Fuel Nozzle Split for Lower Aircraft 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 effectively.
Innovation Solution
The gas turbine engine is configured with specific fuel spray nozzle arrangements and operates using sustainable aviation fuel (SAF), optimizing fuel distribution and combustion to achieve reduced nvPM emissions through defined emissions index ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If traditional kerosene-based jet fuels are used, then fuel availability and energy density are maintained, but nvPM emissions are higher
Solution Approach 1:
The patent changes the fuel parameter from traditional kerosene-based jet fuel to sustainable aviation fuel (SAF), which has different chemical composition and combustion characteristics. This parameter change reduces nvPM emissions while maintaining fuel functionality, directly addressing the contradiction between harmful emissions and fuel adaptability
Solution Approach 2:
The patent employs a composite fuel system combining SAF with traditional jet fuel formulations, creating a hybrid combustion process that leverages the lower emission properties of SAF while maintaining compatibility with existing engine infrastructure, thus reducing nvPM without completely sacrificing fuel versatility
2Power
If fuel flow rate is increased to maintain thrust, then power output is maintained, but nvPM emissions increase
Solution Approach 1:
The patent implements dynamic fuel spray nozzle control that adjusts fuel flow rates and injection patterns in real-time based on operating conditions. This dynamic adjustment allows the system to optimize the balance between maintaining required thrust and minimizing nvPM emissions by adapting fuel delivery to match actual power demands
Solution Approach 2:
The patent divides the fuel injection system into multiple spray nozzles with differential fuel flow rates, creating segmented fuel delivery zones within the combustor. This segmentation allows different regions to operate at different fuel-to-air ratios, optimizing both power output and emission control simultaneously
3Object-generated harmful factors
If SAF is used, then environmental impact is reduced, but combustion characteristics differ from traditional fuels
Solution Approach 1:
The patent incorporates feedback control mechanisms that monitor combustion parameters and adjust fuel injection accordingly. This feedback system compensates for the different combustion characteristics of SAF compared to traditional kerosene, maintaining combustion stability and reliability while preserving the environmental benefits of SAF
Solution Approach 2:
The patent employs preliminary pre-mixing of fuel and air before combustion, creating optimized mixture conditions that account for SAF's different combustion properties. This preliminary action ensures stable and reliable combustion by preparing the fuel-air mixture in advance, compensating for SAF's atypical combustion behavior
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 results in reduced nvPM emissions, minimizing soot deposits, contrail formation, and improving local air quality, particularly at idle and cruise conditions, thereby reducing environmental impact.
Implementation Method 1
a combustor, comprising a combustion chamber and a plurality of fuel spray nozzles configured to inject fuel into the combustion chamber
Data Source
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AI summary
A gas turbine engine (10) for an aircraft is disclosed. The gas turbine engine comprises: a combustor (16), comprising a combustion chamber (120) and a plurality of fuel spray nozzles (124) configured to inject fuel into the combustion chamber (120), wherein the plurality of fuel spray nozzles (124) comprises a first subset (124A) of fuel spray nozzles (124) and a second subset (124B) of fuel spray nozzles (124), wherein the combustor (16) is operable in a condition in which each of the fuel spray nozzles of the first subset (124A) of fuel spray nozzles (124) is supplied with fuel at a greater fuel flow rate than each of the fuel spray nozzles of the second subset (124B) of fuel spray nozzles (124), wherein a ratio of the number of fuel spray nozzles (124) in the first subset (124A) of fuel spray nozzles (124) to the number of fuel spray nozzles (124) in the second subset (124B) of fuel spray nozzles (124) is in the range of 1:2 to 1:5. A thrust nvPM emissions index ratio is defined as: EImaxTOFmaxTOEIidleFidle 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; 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; FmaxTO is the thrust of the gas turbine engine (10) at around 100% available thrust in kN for the given operating conditions; and Fidle is the thrust of the gas turbine engine (10) at around 7% available thrust in kN for the given operating conditions. The thrust nvPM emissions index ratio is greater than 0.001. The gas turbine engine (10) is configured to provide fuel comprising a sustainable aviation fuel (SAF) to the plurality of fuel spray nozzles (124). Also disclosed is a method of operating the gas turbine engine.