Multi-point Centerbody Injector for Compact Gas Turbine Combustion
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Solution Overview
Problem
Conventional gas turbine engine combustion designs that aim for high-energy combustion often result in increased combustion instability, structural damage, and longer combustor lengths, which conflict with the need to minimize emissions and maintain compact engine design.
Innovation Solution
A multi-point centerbody injector mini mixing fuel nozzle assembly with radially oriented air inlet ports and fluid injection ports, which produces a compact, non-swirl or low-swirl premixed flame, achieving higher energy combustion with reduced emissions and stability issues while maintaining or decreasing combustor size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If an axially oriented vane or swirler is incorporated in serial combination with a fuel injector to improve fuel-air mixing and atomization, then higher-energy combustion is produced, but combustion instability increases and combustor length increases
Solution Approach 1:
The fuel injection system is segmented into multiple injection points (central port and multiple radial ports) distributed around the combustor perimeter, allowing independent control of fuel injection zones. This segmentation enables precise fuel-air mixing without requiring large combustion swirls, thereby maintaining combustion stability while achieving high-energy combustion through distributed injection points
Solution Approach 2:
Different regions of the combustor are provided with different injection characteristics - the central port provides one injection pattern while the radial ports provide different injection patterns. This local differentiation allows optimization of fuel-air mixing in specific zones without inducing global combustion instability, resolving the contradiction between combustion energy and stability
2Power
If an axially oriented vane or swirler is incorporated in serial combination with a fuel injector to improve fuel-air mixing and atomization, then higher-energy combustion is produced, but combustor length increases
Solution Approach 1:
The injection system transitions from a single axial dimension to multiple dimensions by incorporating radial ports distributed around the combustor perimeter. This multi-dimensional injection arrangement achieves effective fuel-air mixing and high-energy combustion within a more compact axial length, eliminating the need for long combustors required by conventional axial swirlers
3Power
If larger combustion swirls are produced to improve fuel-air mixing, then higher-energy combustion is achieved, but emissions increase and structural damage risk increases
Solution Approach 1:
The system replaces the mechanical swirler vanes that generate large combustion swirls with a multi-point injection system using radial ports. This substitution achieves effective fuel-air mixing through injection geometry and distribution rather than mechanical swirl generation, thereby reducing emissions and the risk of structural damage from excessive combustion tones and hot spots
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 solution provides finer combustion dynamics control, reduces hot spots, and increases structural life by producing a higher energy output with shorter flame lengths, mitigating combustion instability and emissions while maintaining or reducing combustor size.
Implementation Method 1
The outer sleeve and the centerbody define a premix passage radially therebetween... The fluid cavity wall defines a fluid cavity and a second fluid injection port in fluid communication with the fluid cavity. The second fluid injection port is in fluid communication with the premix passage.
Implementation Method 2
A serial combination of a radially oriented first air inlet port, a radially and axially oriented fluid injection port, and a radially oriented second air inlet port may provide a compact, non-swirl or low-swirl premixed flame
Implementation Method 3
Typical combustors incorporate one or more fuel nozzles whose function is to introduce liquid or gaseous fuel into an air flow stream so that it can atomize and burn
Data Source
AI summary
The present disclosure is directed to a fuel injector for a gas turbine engine. The fuel injector includes an end wall defining a fluid chamber, a centerbody, an outer sleeve surrounding the centerbody from the end wall toward a downstream end of the fuel injector, and a fluid cavity wall. The centerbody includes an axially extended outer wall and inner wall extended from the end wall toward the downstream end of the fuel injector. The outer wall, the inner wall, and the end wall together define a fluid conduit extended in a first direction toward the downstream end of the fuel injector and in a second direction toward an upstream end of the fuel injector. The fluid conduit is in fluid communication with the fluid chamber. The outer wall defines at least one radially oriented fluid injection port in fluid communication with the fluid conduit. The outer sleeve and the centerbody define a premix passage radially therebetween and an outlet at the downstream end of the premix passage. The outer sleeve further defines a plurality of radially oriented first air inlet ports in circumferential arrangement at a first axial portion of the outer sleeve, and a plurality of radially oriented second air inlet ports in circumferential arrangement at a second axial portion of the outer sleeve. The fluid cavity wall is disposed axially between the first air inlet port and the second air inlet port and extends radially from the outer sleeve toward the centerbody. The fluid cavity wall defines a fluid cavity and a second fluid injection port in fluid communication with the fluid cavity. The second fluid injection port is in fluid communication with the premix passage.