Aircraft Combustor Fuel Nozzle Split for Sustainable Aviation Fuel
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The use of fuels different from traditional kerosene-based jet fuels, such as sustainable aviation fuels, presents challenges in terms of different fuel properties, including higher calorific value, thermal stability, and viscosity, which affect combustion efficiency and emissions in gas turbine engines.
Innovation Solution
A gas turbine engine design with a combustor featuring a subset of fuel spray nozzles supplied with more fuel than another subset, a ratio of 1:2 to 1:5, and fuel-oil heat exchangers to control fuel temperature, viscosity, and heat transfer to improve combustion efficiency and reduce emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If fuels with higher calorific value are used, then combustion efficiency is improved, but fuel temperature control becomes more difficult due to higher thermal stability
Solution Approach 1:
The patent changes the temperature parameter of the fuel by introducing fuel-oil heat exchangers that heat the fuel to specific temperature ranges (100-200°C) before injection. This parameter change allows fuels with higher thermal stability and calorific value to be properly atomized and combusted efficiently while preventing coking.
Solution Approach 2:
The patent uses fuel-oil heat exchangers as intermediary devices between the fuel storage system and the combustion chamber. These heat exchangers mediate the temperature of the fuel, transferring heat from hot engine oil to the fuel, thereby controlling fuel temperature and viscosity to optimize combustion while preventing harmful effects of high thermal stability.
2Ease of operation
If fuel is heated to reduce viscosity, then fuel flow and atomization are improved, but coking increases due to higher thermal stability
Solution Approach 1:
The patent precisely controls the temperature parameter within an optimal range (100-200°C) to achieve the right balance: heating enough to reduce viscosity and improve atomization, but not so much as to cause excessive coking. This controlled parameter change resolves the contradiction between ease of operation and harmful effects.
Solution Approach 2:
The patent implements dynamic temperature control through fuel-oil heat exchangers that adjust fuel temperature based on operating conditions. The system dynamically balances viscosity reduction for proper flow and atomization against coking prevention, adapting to different flight phases and fuel types.
3Use of energy by moving object
If more fuel is supplied to certain spray nozzles, then combustion efficiency is improved, but emissions of non-volatile particulate matter increase
Solution Approach 1:
The patent applies local quality by differentiating fuel supply to different nozzle subsets. The first subset of nozzles receives heated fuel with optimized temperature and viscosity characteristics, while the second subset receives fuel at different conditions. This local differentiation allows efficient combustion in critical zones while controlling emissions in other zones.
Solution Approach 2:
The patent segments the fuel injection system into two distinct subsets of spray nozzles with different operating characteristics. This segmentation allows independent optimization of each subset's fuel supply parameters, enabling the system to achieve both high combustion efficiency and low nvPM emissions by distributing fuel strategically across different combustion zones.
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
The solution enhances combustion efficiency, reduces coking, and decreases non-volatile particulate matter (nvPM) emissions, improving engine performance and emissions profiles when using sustainable aviation fuels.
Implementation Method 1
transferring heat from oil to the fuel in the one or more fuel-oil heat exchangers; and providing the fuel from the one or more fuel-oil heat exchangers to the plurality of fuel spray nozzles; wherein heat is transferred from the oil to the fuel in the one or more fuel-oil heat exchangers to raise a temperature of the fuel to an average of at least 135° C. on injection of the fuel into the combustion chamber
Implementation Method 2
transferring heat from the oil to the fuel in the one or more fuel-oil heat exchangers to lower a viscosity of the fuel to 0.58 mm2/s or lower on injection of the fuel into the combustion chamber
Implementation Method 3
a combustor, comprising a combustion chamber and a plurality of fuel spray nozzles configured to inject fuel into the combustion chamber
Implementation Method 4
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 method of operating a gas turbine engine; the gas turbine engine includes a combustor. The combustor includes a combustion chamber and a plurality of fuel spray nozzles configured to inject fuel into the combustion chamber. The plurality of fuel spray nozzles includes a first subset of fuel spray nozzles and a second subset of fuel spray nozzles. The combustor is operable in a condition in which the first subset of fuel spray nozzles are supplied with more fuel than the second subset of fuel spray nozzles. 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. The method includes: providing fuel to the one or more fuel-oil heat exchangers. Also provided is a gas turbine engine for an aircraft.