Lean Burn Fuel Injector Splitter Oxidation Prevention
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Solution Overview
Problem
Lean burn fuel injectors for gas turbine engines face issues with overheating and oxidation of the second splitter, which affects the formation of the S-shaped recirculation zone and flame stabilization, leading to compromised efficiency and emissions performance.
Innovation Solution
A lean burn fuel injector design featuring a second splitter with a frusto-conical convergent portion and a connecting member forming a sharp edge, where the frusto-conical divergent downstream portion of the second splitter is arranged upstream of the first splitter, and the connecting member is equipped with apertures to supply coolant, aiding in preventing oxidation and maintaining the S-shaped recirculation zone.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the second splitter is used for flame stabilisation, then flame stabilisation is improved, but the second splitter overheats and oxidises
Solution Approach 1:
A connecting member is introduced as an intermediary component between the first and second splitters. This connecting member provides a cooled surface that serves as an alternative flame stabilisation location, thereby protecting the second splitter from direct flame contact and oxidation while maintaining reliable flame stabilisation through the connecting member's cooled surface.
Solution Approach 2:
The invention changes the thermal parameter of the connecting member by providing cooling to it, creating a temperature differential between the cooled connecting member and the hot flame zone. This parameter change allows the connecting member to serve as a heat sink and protected flame stabilisation surface, preventing oxidation of the second splitter.
2Object-affected harmful factors
If the second splitter is cooled to prevent oxidation, then oxidation resistance is improved, but the cooled second splitter may still oxidise and reduce the diameter affecting the S-shaped recirculation zone
Solution Approach 1:
The connecting member acts as an intermediary flame stabilisation surface that is specifically cooled and positioned to protect the S-shaped recirculation zone geometry. By providing flame stabilisation on the connecting member rather than the second splitter, the invention prevents diameter reduction of the recirculation zone while maintaining oxidation resistance.
3Object-generated harmful factors
If the mixture of pilot fuel and air is spaced radially from the main fuel and air mixture, then emissions performance is improved, but power efficiency is compromised
Solution Approach 1:
The invention uses the axial dimension (along the flow direction) in addition to the radial dimension for mixture separation. The first and second splitters create axial spacing between the pilot and main fuel/air mixtures, while the connecting member provides a transition surface. This multi-dimensional arrangement allows adequate separation for emissions control while maintaining the coaxial alignment needed for power efficiency.
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 design effectively prevents oxidation of the second splitter, maintains the S-shaped recirculation zone, and enhances the combustion efficiency and emissions performance by ensuring consistent flame stabilization.
Implementation Method 1
the connecting member is equipped with apertures to supply coolant, aiding in preventing oxidation
Implementation Method 2
The first and second splitters enable an S-shaped recirculation zone to form more consistently
Implementation Method 3
the mixture of pilot fuel and air from the inner pilot air-blast fuel injector and the mixture of main fuel and air from the outer main air-blast fuel injector
Data Source
AI summary
A lean burn fuel injector has a head which has a coaxial arrangement of an inner pilot air-blast fuel injector and an outer main air-blast fuel injector. The pilot fuel injector comprises coaxially arranged inner and outer air swirler passages. The main fuel injector comprises coaxially arranged inner and outer air swirler passages. A first splitter is arranged between the passages. The first splitter has a conical divergent downstream portion. A second splitter is arranged radially within and spaced from the first splitter. The second splitter has a conical convergent portion and a conical divergent downstream portion. The downstream end of the second splitter is upstream of the downstream end of the first splitter. A connecting member connects the downstream end of the second splitter and the downstream portion of the first splitter upstream of the downstream end of the first splitter to form a sharp edge.