Fuel Injector Annular Vortex Mixing for Gas Turbine Combustion
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Solution Overview
Problem
Current fuel injectors for gas turbine engines do not effectively achieve lean burn combustion while maintaining combustion efficiency, as they fail to optimize fuel/air mixing and atomization.
Innovation Solution
A fuel injector design featuring an annular passage with a fuel layer vortex and an air layer vortex, where the fuel and air vortices rotate in the same direction, forming a swirling air flow that impinges on a sheet of swirling fuel to achieve atomized fuel spray, enhancing fuel/air mixing and reducing orifice erosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional fuel injection systems are used to deliver fuel to the combustion chamber, then fuel can be supplied to the combustor, but effective lean burn combustion cannot be achieved due to poor fuel/air mixing and atomization
Solution Approach 1:
The annular passage is segmented into an outer-diameter upstream subsection for fuel layer vortex and an inner-diameter upstream subsection for air layer vortex. This segmentation allows separate control and optimization of fuel and air flows, enabling effective lean burn combustion while maintaining manageable system complexity through modular design
Solution Approach 2:
The air layer vortex is nested within the annular space between the fuel layer vortex and the annular inner passage wall. This nested configuration allows compact arrangement of fuel and air paths, achieving efficient fuel/air mixing without increasing overall device complexity
2Manufacturing precision
If fuel is delivered through an annular passage to create an annular liquid fuel film, then fuel can be discharged, but effective atomization is not achieved because the liquid fuel film moves much more rapidly than the swirling air streams
Solution Approach 1:
The system transitions from a static annular liquid fuel film to dynamic vortices - both fuel layer vortex and air layer vortex. This dynamic configuration creates controlled turbulence and mixing zones, significantly improving atomization quality while reducing the relative velocity differential between fuel and air streams through co-rotation
Solution Approach 2:
The invention changes the flow regime parameter from laminar annular film flow to turbulent vortex flow. By inducing rotational motion in both fuel and air layers, the system transforms the velocity profile and enhances mixing, achieving effective atomization without requiring excessive speed reduction
3Productivity
If swirling air streams are used to atomize the liquid fuel film, then some atomization occurs, but lean burn combustion cannot be achieved due to insufficient fuel/air mixing
Solution Approach 1:
The fuel layer vortex and air layer vortex are merged within the annular passage, creating a pre-mixed fuel/air vortex before discharge. This merging occurs through the interaction zone between the two vortices, producing high-quality fuel/air mixture that enables efficient lean burn combustion while maintaining proper stoichiometry
Solution Approach 2:
Fuel and air are preliminarily mixed within the annular passage through the interacting vortices before being discharged into the combustion chamber. This preliminary mixing action ensures optimal fuel/air ratio is achieved upstream, facilitating lean burn combustion and improving overall combustion 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 improves fuel atomization, reduces orifice erosion, and enhances combustion efficiency by optimizing fuel/air mixing, enabling lean burn combustion in gas turbine engines.
Implementation Method 1
guiding a fuel layer vortex formed in the outer-diameter upstream subsection to flow along the annular outer passage wall
Implementation Method 2
guiding an air layer vortex formed in the inner-diameter upstream subsection to fill into and pass through an annular space defined by and radially between the fuel layer vortex and the annular inner passage wall
Implementation Method 3
generating a swirling air flow to impinge on a sheet of swirling fuel formed by the fuel layer vortex discharged from the annular passage, resulting in atomized fuel spray
Data Source
AI summary
A fuel injector for a fuel spray nozzle of a gas turbine engine combustor includes an angular lip axially projecting into an upstream section of an annular passage to guide a fuel layer vortex to flow along a radially outer passage wall of the annular passage and to guide an air layer vortex to fill into and pass through an annular space between the fuel layer vortex and a radially-inner passage wall of the annular passage. The air layer vortex is free of mixing with the fuel layer vortex before the fuel layer vortex is discharged from the annular passage for fuel atomization.