Hydrogen Fuel Nozzle Swirler Geometry for Flashback Mitigation
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Solution Overview
Problem
Current fuel nozzle designs in gas turbine engines face durability issues due to flame holding and flashback when using hydrogen-based fuels, necessitating improved cooling and mitigation strategies.
Innovation Solution
A fuel nozzle assembly with a concentrically arranged liquid swirler and radial air swirler design, featuring angled walls and radiused surfaces to minimize flame holding, combined with a contoured outer surface and aligned air passages to enhance atomization and mixing, thereby preventing flashback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional fuel nozzle designs are used with hydrogen-based fuels, then the fuel nozzle can supply fuel to the combustion chamber, but flame holding and flashback occur leading to durability issues
Solution Approach 1:
The patent applies curvature by providing a radiused inner surface on the end cap instead of a sharp edge. This curved geometry prevents flame holding by eliminating the sharp corners where flames could be trapped, thereby resolving the contradiction between maintaining fuel supply capability and preventing harmful flame holding effects.
Solution Approach 2:
The patent changes geometric parameters by angling the liquid swirler inner wall end portion and outer wall end portion radially outward, and angling the RAS inner wall end portion radially inward. These parameter modifications alter the flow characteristics and prevent flashback by changing the geometry of the fuel-air mixture formation zone.
2Productivity
If the liquid swirler and radial air swirler are concentrically disposed with angled walls, then atomization and mixing are enhanced, but the device complexity increases
Solution Approach 1:
The patent applies nesting by concentrically disposing the liquid swirler within the radial air swirler, creating a multi-layered structure where the liquid swirler is nested inside the gas swirler. This nested arrangement enhances atomization and mixing efficiency while maintaining a compact, integrated design that does not excessively increase device complexity.
Solution Approach 2:
The patent merges the liquid fuel delivery system and gas fuel delivery system into a single integrated fuel nozzle assembly with concentric passages. By combining these functions into one unified structure with shared cooling passages, the design achieves enhanced mixing while avoiding the complexity of separate independent nozzles.
3Object-affected harmful factors
If the end cap has a radiused inner surface parallel to the RAS inner wall end portion, then flame holding is minimized, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies curvature by providing a radiused inner surface on the end cap that is parallel to the RAS inner wall end portion. This curved geometry prevents flame holding by eliminating sharp corners, and the parallel orientation provides a clear manufacturing guideline that actually simplifies precision requirements compared to complex angular geometries.
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 reduces flame holding and flashback, enhancing durability and stability of fuel nozzles when using hydrogen-based fuels by improving cooling and mixing efficiency.
Implementation Method 1
a liquid swirler concentrically disposed about the inflow tube, the liquid swirler including a liquid swirler inner wall having a liquid swirler inner wall end portion angled radially outward from the nozzle axis, a liquid swirler outer wall having a liquid swirler outer wall end portion angled radially outward from 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 design effectively reduces flame holding and flashback, enhancing durability and stability of fuel nozzles when using hydrogen-based fuels by improving cooling and mixing efficiency
Data Source
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AI summary
A fuel nozzle (54) for a gas turbine engine combustor includes a fuel nozzle assembly (66) including an inflow tube (74) disposed along and a nozzle axis (F), the inflow tube (74) defining an inner air passage (76A) and a liquid swirler (80) concentrically disposed about the inflow tube (74), the liquid swirler (80) including a liquid swirler inner wall (82) having a liquid swirler inner wall end portion (83) angled radially outward from the nozzle axis (F), a liquid swirler outer wall (84) having a liquid swirler outer wall end portion (88) angled radially outward from 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) having an RAS inner wall end portion (98) angled radially inward toward the nozzle axis (F), 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) includes a radiused inner surface and a contoured outer surface, and the radiused inner surface is parallel to the RAS inner wall end portion (93).