Combustor Nozzle Flow Split for Lower nvPM With SAF
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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, especially with the transition to sustainable aviation fuel (SAF).
Innovation Solution
The gas turbine engine is configured with a combustor featuring a plurality of fuel spray nozzles, including a first and second subset, where the first subset receives a higher fuel flow rate, and operates with a defined emissions index ratio to optimize the use of SAF, thereby reducing nvPM emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the gas turbine engine uses sustainable aviation fuel (SAF), then environmental sustainability is improved, but non-volatile particulate matter (nvPM) emissions increase
Solution Approach 1:
The fuel spray nozzles are divided into two subsets: a first subset with higher fuel flow rates and a second subset with lower fuel flow rates. This segmentation allows different regions of the combustor to receive optimized fuel quantities, improving combustion efficiency and reducing nvPM emissions while maintaining SAF usage
Solution Approach 2:
Different subsets of fuel spray nozzles are assigned different fuel flow rate characteristics tailored to their specific locations and functions within the combustor. The first subset operates at higher flow rates for regions requiring intense combustion, while the second subset operates at lower flow rates for regions where excessive fuel would increase nvPM emissions
2Power
If the fuel flow rate to all nozzles is increased, then power output is improved, but nvPM emissions increase
Solution Approach 1:
The fuel spray nozzles are divided into two subsets: a first subset with higher fuel flow rates and a second subset with lower fuel flow rates. This segmentation allows different regions of the combustor to receive optimized fuel quantities, improving combustion efficiency and reducing nvPM emissions while maintaining SAF usage
Solution Approach 2:
The system changes the fuel flow rate parameter differently for different subsets of nozzles based on operating conditions. By dynamically adjusting fuel distribution parameters between the two subsets, the engine optimizes the balance between power output and nvPM emissions
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 nvPM emissions, minimizing soot deposits, contrail strength, and environmental impact, improving local air quality, and optimizing fuel distribution and combustion within the engine.
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 1:3 to 1:6. A MTO nvPM emissions index ratio is defined as:EImaxTO,SAFEImaxTO,FFwhere: EImaxTO,SAF is the nvPM emissions index in mg/kg of the gas turbine engine when operating at around 100% available thrust for given operating conditions if a fuel provided to the plurality of fuel spray nozzles comprises a sustainable aviation fuel (SAF); and EImaxTO,FF is the nvPM emissions index in mg/kg of the gas turbine engine when operating at around 100% available thrust for the given operating conditions if a fuel provided to the plurality of fuel spray nozzles is a fossil-based hydrocarbon fuel. The MTO nvPM emissions index ratio of the gas turbine engine is less than 1. The gas turbine engine is configured to provide fuel comprising a SAF to the plurality of fuel spray nozzles. Also disclosed are methods of operating the gas turbine engine.