Combustor Nozzle Flow Split for Lower Aircraft Engine nvPM
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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
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 using sustainable aviation fuel (SAF) to optimize the idle-MTO nvPM emissions index ratio, thereby reducing nvPM emissions.
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 applies parameter changes by adjusting the fuel flow rate distribution parameter between different nozzle subsets. By varying the ratio of fuel flow rates between the first subset (higher flow) and second subset (lower flow) of nozzles, the engine optimizes combustion characteristics to reduce nvPM emissions when using SAF, while maintaining adaptability to different fuel types through controlled parameter adjustment
2Power
If fuel flow rate is increased to maintain engine performance, then power output is maintained, but nvPM emissions increase
Solution Approach 1:
The patent segments the fuel injection system into two distinct subsets of nozzles with different flow rate characteristics. The first subset operates at higher fuel flow rates while the second subset operates at lower fuel flow rates. This segmentation allows the engine to maintain overall power output through combined fuel injection while optimizing local combustion conditions in each subset to reduce nvPM emissions, particularly when using SAF
Solution Approach 2:
The patent applies local quality by giving different fuel flow rate characteristics to different subsets of nozzles. The first subset is configured for higher fuel flow rates to ensure adequate power output, while the second subset uses lower fuel flow rates to optimize combustion efficiency and reduce nvPM emissions. This localized differentiation of fuel injection quality allows simultaneous achievement of power maintenance 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 decreased contrail strength and dispersal time, 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
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 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; 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; 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.