Injector Ring Vortex Generators for Gas Turbine Mixing
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Solution Overview
Problem
Existing gas turbine sequential combustion systems face challenges in achieving efficient mixing of fuel and hot gas with minimal pressure drop and complex geometries or sealing systems, which affect combustion performance and emissions.
Innovation Solution
A mixing arrangement featuring a circular injector ring with a symmetric aerodynamic profile and vortex generators or lobes, allowing for multipoint injection of liquid fuel, air, and fuel gas, independent of momentum flux ratio, to enhance mixing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high momentum flux ratios are used to achieve good mixing levels, then mixing performance is improved, but pressure drop increases
Solution Approach 1:
The fuel injection system is divided into multiple injector rings with multiple injection nozzles distributed around the circumference. This segmentation allows fuel to be injected at multiple locations simultaneously, improving mixing efficiency without requiring high momentum flux ratios that would cause excessive pressure drop
Solution Approach 2:
Vortex generators or lobes are provided on the injector rings to create localized fluid-dynamic structures at specific injection points. These local modifications generate vortices that enhance fuel-air mixing in the immediate vicinity of each nozzle, achieving good overall mixing levels without increasing system-wide pressure drop
2Manufacturing precision
If complicated geometries are used to achieve effective mixing, then mixing performance is improved, but device complexity increases
Solution Approach 1:
The complex mixing task is divided into multiple simpler injection points around the circumference. Each injector ring with its nozzles and vortex generators constitutes a modular unit, and multiple such units work together to achieve the desired mixing performance, avoiding the need for a single complicated geometry
Solution Approach 2:
Instead of complicating the axial geometry, the invention distributes injection nozzles and vortex generators around the circumferential dimension. This multi-dimensional approach achieves effective mixing by utilizing the radial and circumferential dimensions, keeping the axial geometry relatively simple
3Reliability
If complex sealing systems are used between fuel injector and hot gas path, then combustion performance is improved, but device complexity increases
Solution Approach 1:
The fuel injection system is segmented into multiple independent injector rings that can be positioned within the hot gas path. This segmentation allows for simpler sealing arrangements at each individual injection point compared to a single complex sealing system, while maintaining combustion performance through multiple injection locations
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 configuration improves mixing homogeneity, reduces emissions, and achieves a shorter mixing length, enabling a compact design suitable for annular and cylindrical burners with lower NOx emissions and flexibility in fuel injection.
Implementation Method 1
vortex generators are provided on said at least one injector ring
Implementation Method 2
said at least one injector ring has the aerodynamical profile of a symmetric airfoil
Data Source
Figure 1~2
Figure 3~3c
Figure 4~5
AI summary
The invention relates to a mixing arrangement for mixing a fuel (13, 15) with a stream of oxygen containing gas flowing along an axis (16) in an axial channel, especially in the second combustor of a gas turbine with sequential combustion. The mixing is improved and the mixing length reduced by said mixing arrangement comprising an injector (10) with at least one injector ring (11), which is passed by said stream of gas inside and outside.