Hydrogen Fuel Nozzle Assembly With Nested Swirlers for Flashback Resistance
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Solution Overview
Problem
Current fuel nozzle designs for gas turbine engines face durability issues due to flame holding and flashback when using hydrogen-based fuels, particularly in low flow velocity regions.
Innovation Solution
The design incorporates a fuel nozzle assembly with a concentrically arranged liquid swirler, radial air swirler, and guide swirler, featuring a radiused inner surface and contoured outer surface on the end cap to enhance cooling and prevent flame holding, utilizing hydrogen-based fuels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional fuel nozzle designs are used with hydrogen-based fuels, then the nozzle structure is simple and easy to manufacture, but flame holding and flashback occur causing durability issues
Solution Approach 1:
The fuel nozzle is divided into multiple functional segments: an inner swirler for hydrogen fuel, an outer swirler for cooling air, and a liquid swirler for water injection. Each segment operates independently to address specific problems - the inner swirler prevents flashback, the outer swirler provides cooling, and the liquid swirler reduces NOx emissions. This segmentation allows the complex functionality to be achieved while maintaining manageable design and manufacturing.
Solution Approach 2:
The patent implements a nested configuration where the inner swirler is positioned within the outer swirler, which in turn is surrounded by the liquid swirler. This nested arrangement allows multiple functional elements to be integrated in a compact space, achieving flame prevention, cooling, and emission control without proportionally increasing overall device complexity.
2Object-generated harmful factors
If hydrogen-based fuels are used, then cleaner combustion and lower emissions are achieved, but flame holding and flashback occur reducing operational stability
Solution Approach 1:
The inner swirler is designed to generate a high-velocity hydrogen fuel jet that creates a recirculation zone immediately at the nozzle exit. This preliminary action establishes a protective flame front before the combustion process begins, preventing flashback from propagating back into the nozzle. The swirler geometry is specifically optimized to create this protective zone in advance.
Solution Approach 2:
The patent modifies flow parameters by introducing multiple swirling flows with different velocities and directions. The inner swirler creates a high-velocity core flow, while the outer swirler provides a lower-velocity cooling flow. This parameter differentiation stabilizes the combustion process by maintaining appropriate residence time for complete combustion while preventing premature ignition.
3Reliability
If cooling is enhanced to prevent flame holding, then durability is improved, but air flow requirements increase affecting system performance
Solution Approach 1:
The outer swirler delivers cooling air to specific high-heat zones - particularly the nozzle exit region and inner swirler surfaces - rather than providing uniform cooling throughout. This localized cooling approach uses minimal air quantities to protect critical areas from thermal damage and flame holding, avoiding the need for large volumes of cooling air that would affect combustion performance.
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 improved design reduces flame holding potential and enhances cooling, ensuring stable operation with hydrogen-based fuels by eliminating separation zones and increasing air flow velocity.
Implementation Method 1
a liquid swirler concentrically disposed about the inflow tube. The liquid swirler includes a liquid swirler inner wall, a liquid swirler outer wall having a liquid swirler outer wall end portion at a downstream-most position and angled radially inward toward the nozzle axis, and an annular liquid passage defined therebetween. The fuel nozzle assembly further includes a radial air swirler (RAS) concentrically disposed about the liquid swirler outer wall
Implementation Method 2
The end cap has a radiused inner surface and a contoured outer surface. The improved design reduces flame holding potential and enhances cooling, ensuring stable operation with hydrogen-based fuels by eliminating separation zones and increasing air flow velocity.
Data Source
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AI summary
A fuel nozzle (54) for a gas turbine engine combustor includes an inflow tube (74) disposed along and a nozzle axis (F), the inflow tube (74) defining an inner air passage (76) and a liquid swirler (80) concentrically disposed about the inflow tube (74). The liquid swirler (80) includes a liquid swirler inner wall (82), a liquid swirler outer wall (84) having a liquid swirler outer wall end portion (88) at a downstream-most position and angled radially inward toward the nozzle axis (F), and an annular liquid passage (86) defined therebetween. The fuel nozzle assembly (66) further includes a radial air swirler (RAS) (90) concentrically disposed about the liquid swirler outer wall (84), the RAS (90) including an RAS inner wall (92), an RAS outer wall (94) having an end cap (98) at a downstream-most position, and an annular gas passage (96) defined therebetween. The end cap (98) has a radiused inner surface and a contoured outer surface. The fuel nozzle assembly (66) further includes a guide swirler (56) disposed concentrically about the RAS outer wall (94), the guide swirler (56) comprising an annular air passage (57) angled radially inward toward the nozzle axis (F).