Gas Turbine Combustor Nozzle Ratio for SAF nvPM Reduction
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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, particularly with the transition to sustainable aviation fuel (SAF).
Innovation Solution
The gas turbine engine is configured with a combustor featuring distinct subsets of fuel spray nozzles, where one subset receives a higher fuel flow rate, and operates with sustainable aviation fuel to maintain an idle-MTO nvPM emissions index ratio below specific thresholds, optimizing fuel distribution and combustion.
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 emissions increase
Solution Approach 1:
The patent applies parameter changes by adjusting combustion chamber operating parameters (temperature, pressure, air-fuel ratio) when transitioning between different fuel types. This allows the engine to optimize combustion characteristics for each fuel type, thereby reducing nvPM emissions while maintaining adaptability to various fuels including SAF and traditional kerosene
2Object-generated harmful factors
If fuel composition is changed to sustainable aviation fuel, then environmental impact is reduced, but combustion characteristics and emissions vary requiring operational adjustments
Solution Approach 1:
The patent implements feedback mechanisms where emission sensors monitor nvPM levels and other combustion parameters in real-time. This data feeds back to the control system, which automatically adjusts fuel injection rates, air intake, and ignition timing to optimize combustion and maintain low emissions regardless of fuel type, thereby simplifying operation despite fuel composition changes
3Object-generated harmful factors
If operating parameters are adjusted to reduce nvPM emissions, then environmental performance improves, but engine performance and thrust may be affected
Solution Approach 1:
The patent employs dynamic adjustment of operating parameters based on real-time conditions. The control system continuously modifies fuel injection timing, air-fuel ratio, and combustion chamber pressure to simultaneously optimize both emissions and power output. This dynamic control allows the engine to achieve low nvPM emissions during cruise while maintaining required thrust during takeoff and climb phases
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 non-volatile particulate matter emissions, minimizing soot deposits, contrail strength, and improving local air quality, particularly at idle and cruise conditions, and reducing environmental impact.
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
A gas turbine engine for an aircraft is disclosed. The gas turbine engine comprises: a combustor, comprising a combustion chamber and a plurality of fuel spray nozzles configured to inject fuel into the combustion chamber, wherein the plurality of fuel spray nozzles comprises a first subset of fuel spray nozzles and a second subset of fuel spray nozzles, wherein the combustor is operable in a condition in which each of the fuel spray nozzles of the first subset of fuel spray nozzles is supplied with fuel at a greater fuel flow rate than each of the fuel spray nozzles of the second subset of fuel spray nozzles, wherein a ratio of the number of fuel spray nozzles in the first subset of fuel spray nozzles to the number of fuel spray nozzles in the second subset of fuel spray nozzles is in the range of 1:2 to 1:5. A thrust nvPM emissions index ratio is defined as:EImaxTO/FmaxTOEIidle/Fidlewhere: EIidle is the nvPM emissions index in mg/kg of the gas turbine engine if operating at around 7% available thrust for given operating conditions; EImaxTO is the nvPM emissions index in mg/kg of the gas turbine engine if operating at around 100% available thrust for the given operating conditions; FmaxTO is the thrust of the gas turbine engine at around 100% available thrust in kN for the given operating conditions; and Fidle is the thrust of the gas turbine engine 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 is configured to provide fuel comprising a sustainable aviation fuel (SAF) to the plurality of fuel spray nozzles. Also disclosed is a method of operating the gas turbine engine.