Segmented Premix Nozzle Tip for Gas Turbine Flame Stability
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Solution Overview
Problem
Existing gas turbine combustor nozzle designs face challenges in achieving efficient flame holding and flame propagation due to the energy losses associated with swirling flows, which increase pressure drop and reduce power efficiency, while also limiting the design flexibility of flame shape and recirculation zones.
Innovation Solution
The development of a premix fuel nozzle architecture that utilizes axial flow instead of swirl flow, featuring a burner tube with a nozzle tip designed to generate multiple recirculation zones of varying radial extent through strategically fabricated segments, allowing for strong flame holding and flame propagation with customizable flame shapes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If swirling flow is used to create recirculation zones for flame holding, then flame stability is improved, but pressure drop increases and power efficiency decreases
Solution Approach 1:
The nozzle tip is divided into multiple segments (at least two) that are circumferentially spaced apart, with each segment independently contributing to create multiple separate recirculation zones. This segmentation allows the flow to be divided into distinct regions, each forming its own vortex, thereby maintaining flame stability through multiple localized recirculation zones while reducing the overall energy loss compared to a single large swirl-induced recirculation zone.
Solution Approach 2:
Each segment of the nozzle tip is designed with specific geometric characteristics (downstream face angles between 105°-165°, heights, widths) that are optimized to create recirculation zones with desired local properties. The segments can have different dimensions and orientations to produce recirculation zones with varying radial extents, allowing local optimization of flame holding characteristics while minimizing overall pressure drop.
2Reliability
If swirl flow is used to increase recirculation zone size, then flame holding capability is improved, but design flexibility of flame shape is limited
Solution Approach 1:
The segmentation of the nozzle tip into multiple independent segments allows each segment to be individually designed and optimized for specific flame shaping requirements. The circumferentially spaced segments can be configured with different geometries, angles, and dimensions to create recirculation zones with different radial extents, enabling customized flame shapes while maintaining robust flame holding capability.
Solution Approach 2:
The local geometric properties of each segment (downstream face angle, height, width) can be independently optimized to produce recirculation zones with specific characteristics. This local quality approach allows the creation of non-uniform recirculation zone distributions that can be tailored to achieve desired flame shapes, such as elongated, compact, or distributed flame patterns, while ensuring adequate flame holding in each zone.
3Reliability
If larger nozzle tip size is used to anchor flame, then flame stability is improved, but flow area is reduced and losses increase
Solution Approach 1:
Instead of using a single large nozzle tip structure, the segmented design creates multiple smaller recirculation zones distributed around the circumference. Each segment creates a localized recirculation zone that contributes to overall flame stability without requiring a proportionally large nozzle tip size. This distributes the functional requirement across multiple smaller structures, maintaining flame stability while minimizing the impact on flow area and associated losses.
Solution Approach 2:
The segments are arranged circumferentially around the nozzle tip, utilizing the circumferential dimension to create multiple recirculation zones. This dimensional arrangement allows the formation of multiple recirculation zones without increasing the axial or radial dimensions of the nozzle tip proportionally, thereby maintaining flame stability through distributed recirculation while minimizing interference with the main flow area and reducing energy losses.
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 approach enhances flame stability, increases mass flow recirculation, allows for flexible flame shape design, and improves lean blowout resistance, effectively addressing the inefficiencies and design limitations of swirling flow systems.
Implementation Method 1
at least two recirculation zones with at least two differing radial extents as part of a toroidal vortex generated on the nozzle tip
Implementation Method 2
an axial flow field of an air and fuel mixture flows that through the burner tube and around the nozzle tip and at least two recirculation zones with at least two differing radial extents
Data Source
AI summary
A method of optimizing a premix fuel nozzle for a gas turbine is provided including the step of providing a nozzle that provides, when the gas turbine is in operation, an axial flow field of an air and fuel mixture flows through the burner tube and around the nozzle tip, and at least two recirculation zones with at least two differing radial extents as part of a toroidal vortex generated on the nozzle tip to provide strong flame holding and flame propagation.