Fuel Swirl Nozzle Density for Combustor Efficiency
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Solution Overview
Problem
The performance of fuel swirl nozzles and combustors in gas turbine engines is limited by inefficiencies in fuel atomization and air flow mixing, leading to suboptimal combustion efficiency and increased emissions, particularly in terms of thermal efficiency and propulsive thrust.
Innovation Solution
The design incorporates a combustor assembly with a defined Fuel Atomisation Density parameter, utilizing pre-filming airblast fuel swirl nozzles with a specific configuration of swirl vanes and an additive layer manufacturing process for the air swirlers, which enhances fuel-air mixing efficiency and reduces the size and weight of the fuel swirl nozzle, while maintaining a streamlined fuel stem shroud to minimize aerodynamic losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the quantity of fuel swirl nozzles is increased to improve fuel atomization density, then combustion efficiency is improved, but device complexity increases
Solution Approach 1:
The combustor is divided into multiple combustion zones with N fuel swirl nozzles distributed around the circumference, where N is an integer between 2 and 12. This segmentation allows improved fuel atomization density and combustion efficiency while maintaining manageable device complexity through modular arrangement.
Solution Approach 2:
The patent optimizes the fuel swirl nozzle parameters including the swirl vane geometry, nozzle diameter, and spacing to achieve optimal atomization density. The parameter D_FSN (fuel atomisation density parameter) is defined as a value in the range of 300 to 1,200, with preferred ranges of 400-1,000 and more preferably 500-900, to balance combustion efficiency with device complexity.
2Productivity
If pre-filming airblast fuel swirl nozzles are used to enhance fuel-air mixing, then combustion efficiency is improved, but manufacturing complexity increases
Solution Approach 1:
The pre-filming airblast fuel swirl nozzles incorporate a pre-filming section where fuel is atomized before entering the main combustion zone. This preliminary atomization action enhances fuel-air mixing efficiency in the combustion zone, achieving better combustion efficiency despite increased manufacturing complexity.
Solution Approach 2:
The swirl vane geometry parameters including the number of swirl vanes, their angle, and positioning are optimized to achieve the desired pre-filming effect. The design parameters are carefully controlled to balance the enhanced fuel-air mixing with manufacturing feasibility.
3Volume of moving object
If the combustor casing internal volume is reduced to decrease engine size, then engine compactness is improved, but combustion efficiency deteriorates
Solution Approach 1:
The patent defines the combustor casing internal volume V in cm³ and optimizes it to achieve the target fuel atomisation density parameter D_FSN in the range of 300 to 1,200. This parameter optimization allows reduced combustor volume for compactness while maintaining adequate combustion efficiency through improved fuel atomization density.
Solution Approach 2:
The fuel atomization density is optimized locally at the nozzle level rather than uniformly throughout the combustor. This allows the combustor casing volume to be reduced while maintaining high combustion efficiency in the critical fuel injection zones, achieving compactness without sacrificing overall combustion performance.
4Loss of energy
If streamlined fuel stem shroud is used to minimize aerodynamic losses, then propulsive efficiency is improved, but manufacturing complexity increases
Solution Approach 1:
The fuel stem shroud is designed with a streamlined curved geometry to minimize aerodynamic losses and improve propulsive efficiency. The curved shape reduces flow separation and turbulence, decreasing energy losses despite increased manufacturing complexity compared to simple cylindrical shapes.
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 improves the combustion efficiency by increasing the atomization density of the fuel-air mixture, enhancing the thermal efficiency of the gas turbine engine and reducing emissions, while also simplifying the assembly and maintenance of the fuel swirl nozzle.
Implementation Method 1
the fuel swirl nozzles are pre-filming airblast fuel swirl nozzles that take a fuel feed and, using an arrangement of swirl vanes, atomise this fuel feed into the high-pressure air flow
Implementation Method 2
using an arrangement of swirl vanes, atomise this fuel feed into the high-pressure air flow provided by the high-pressure turbine assembly
Implementation Method 3
The combustion apparatus instigates and facilitates combustion of fuel with relatively high-pressure air received from a compressor stage of the gas turbine engine and thereby adds thermal energy to the relatively high-pressure air
Data Source
Figure 1
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AI summary
A combustor assembly (300) for a gas turbine engine (10), the combustor assembly (300) comprising a combustor casing (310) and an integer quantity N of fuel swirl nozzles (100), the combustor casing (310) defining a total internal volume V of the combustor casing (310), wherein a fuel swirl nozzle density ratio defined as Dfsn=N/V is in the range of 200 to 1.500 (m-3).