Gas Turbine Fuel Injector Vane Mixing Chamber Design
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Solution Overview
Problem
In gas turbine assemblies with axial fuel staging systems, the mixing capability of secondary fuel injectors affects the operating efficiency and emissions, as existing designs may not effectively distribute fuel and air in the secondary combustion zone.
Innovation Solution
A fuel injector with a nozzle featuring circumferentially-spaced vanes that define inlet flow paths, allowing fuel to be discharged into these paths through ports, enhancing the mixing of fuel and compressed air before injection into the secondary combustion zone.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If fuel is injected directly into the secondary combustion zone without proper mixing structure, then the injection process is simple, but the mixing capability of fuel and air is insufficient, reducing operating efficiency and increasing emissions
Solution Approach 1:
The nozzle is segmented into multiple functional components: an inlet portion with circumferentially-spaced vanes that define inlet flow paths, and an outlet portion with a mixing chamber. This segmentation allows each component to perform its specific function - the vanes create controlled flow paths while the mixing chamber facilitates fuel-air mixing, thereby improving mixing capability without creating an overly complex integrated structure
Solution Approach 2:
The mixing chamber acts as an intermediary component between the fuel injection system and the secondary combustion zone. It provides a dedicated space where fuel and compressed air can mix before entering the combustion zone, serving as a mediator that enhances mixing capability while maintaining a relatively simple overall nozzle structure
2Loss of energy
If complex mixing structures are used in the fuel injector, then the mixing capability improves, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The nozzle is divided into distinct segments (inlet portion with vanes, outlet portion with mixing chamber) that can be manufactured separately using standard fabrication techniques, then assembled together. This segmentation maintains ease of manufacture for each component while achieving effective mixing through the combined structure
Solution Approach 2:
The mixing chamber is specifically designed with particular geometric characteristics in the local region where mixing occurs, while other portions of the nozzle maintain simpler geometries. This localized complexity approach improves emissions through enhanced mixing only where needed, without increasing manufacturing difficulty across the entire device
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
This design improves the mixing of fuel and compressed air, leading to increased operating efficiency and reduced emissions in gas turbine assemblies by ensuring thorough fuel distribution within the secondary combustion zone.
Implementation Method 1
Each vane has at least one port defined therein that is in flow communication with the fuel conduit fitting such that fuel from the fuel conduit fitting is dischargeable into at least one of the inlet flow paths via the at least one port
Data Source
AI summary
A fuel injector for a gas turbine combustor includes a fuel conduit fitting and a nozzle having an inlet portion defining a mixing chamber therein. The inlet portion includes a plurality of circumferentially-spaced vanes that define a plurality of inlet flow paths within the mixing chamber. Each vane has at least one port defined therein that is in flow communication with the fuel conduit fitting such that fuel from the fuel conduit fitting is dischargeable into at least one of the inlet flow paths via the at least one port. The resulting fuel/air mixture is delivered into a secondary combustion zone of the gas turbine combustor. A gas turbine including the fuel injector and a method of fabricating the fuel nozzle are also provided.