Serpentine-Cooled Fuel Injector Boss for Hydrogen Flashback Control
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Solution Overview
Problem
Traditional gas turbine combustors struggle with burning high levels of hydrogen and/or pure hydrogen, leading to flame holding or flashback issues, which can cause severe damage to the fuel injectors.
Innovation Solution
A fuel injection assembly with a serpentine cooling passage and a mixing channel design that includes a fuel injector and a boss coupled to the combustion liner, featuring a serpentine cooling passage and premix tubes angled towards a mixing channel to deliver alternative fuels like hydrogen without causing flame holding or flashback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If traditional combustion systems burn high levels of hydrogen and/or pure hydrogen, then NOx emissions are reduced, but flame holding or flashback conditions occur causing severe damage to the fuel injector
Solution Approach 1:
The patent applies preliminary action by introducing cooling air through serpentine cooling passages in the boss structure before the fuel/air mixture reaches the injection tip. This pre-cooling prevents the mixture from becoming too hot and stable, thereby preventing flame holding and flashback conditions that would damage the fuel injector, while still allowing high levels of hydrogen combustion to reduce NOx emissions
2Productivity
If fuel and air are delivered to a secondary combustion zone using traditional AFS fuel injectors, then combustion efficiency is improved, but flame holding conditions occur when burning high levels of hydrogen
Solution Approach 1:
The patent applies local quality by creating different thermal environments in different zones: the serpentine cooling passages provide localized cooling at the boss and injection tip areas to prevent flame holding, while the secondary combustion zone maintains high temperature for efficient hydrogen combustion. This localized thermal management allows high productivity without reliability issues
3Stability of the object's composition
If cross-flow fuel injection is used in axial fuel staging system, then fuel/air mixing is improved, but flashback conditions occur with alternative fuels like hydrogen
Solution Approach 1:
The patent introduces cooling air as an intermediary substance that flows through the serpentine passages and contacts the fuel/air mixture at the injection tip. This intermediary cooling air layer prevents the mixture from achieving the thermal stability required for flashback, while still allowing effective fuel/air mixing to occur in the secondary combustion zone
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 delivers hydrogen and air to a secondary combustion zone, reducing NOx emissions and preventing damage to the injector by mitigating flame holding and flashback conditions.
Implementation Method 1
The serpentine passage includes a first portion that delivers the cooling air to a radially outer surface of the boss and a second portion that delivers the cooling air to a radially inner surface of the boss
Implementation Method 2
the first portion delivers the cooling air to a radially outer surface of the boss and the second portion delivers the cooling air to a radially inner surface of the boss
Data Source
AI summary
Fuel injection assemblies and combustors are provided. The fuel injection assembly includes a fuel injector that is configured to couple to an outer sleeve of the combustor. The fuel injection assembly further comprises a boss that is spaced apart from the fuel injector and is configured to couple to a combustion liner of the combustor. The boss includes a flange portion, an annular wall portion extending from the flange portion, and an interior surface. The boss defines a serpentine cooling passage that extends from an inlet on the flange portion to an outlet on the interior surface.