Undulating Trailing Edge Fuel Injector for Gas Turbine Mixing
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Solution Overview
Problem
In gas turbines with sequential combustion, achieving complete and uniform fuel/oxidant mixing before fuel ignition is challenging, especially when the oxidant temperature exceeds the fuel's self-ignition temperature, leading to potential NOx emissions and flashback issues, while also requiring complex and costly manufacturing processes for fuel injector devices.
Innovation Solution
A fuel injector device with an undulating trailing edge and multiple fuel discharge means arranged between inflection points, utilizing additive manufacturing to create a seamless, monolithic structure that generates small vortices for improved mixing and supports dual-fuel operation through optimized fuel discharge geometries and carrier fluid shielding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the oxidant temperature is increased to improve combustion efficiency, then the flame temperature increases, but NOx emissions increase and flashback risk increases
Solution Approach 1:
The patent applies preliminary action by creating extensive fuel/oxidant mixing before the fuel ignition point. The undulating trailing edge geometry generates vortices that intensify mixing in advance, ensuring complete fuel-oxidant integration before the high-temperature combustion zone is reached. This preliminary mixing allows for more controlled combustion at lower peak temperatures, reducing NOx formation while maintaining combustion efficiency.
2Manufacturing precision
If the fuel discharge means is arranged at the trailing edge inflection points, then fuel/oxidant mixing is intensified through vortices, but the pressure drop across the burner increases
Solution Approach 1:
The patent segments the fuel discharge locations into two distinct groups: fuel discharge means at the trailing edge inflection points (utilizing strong vortices for intense mixing) and additional fuel discharge means between the inflection points (providing supplementary mixing with lower local velocity). This segmentation allows the system to achieve complete fuel-oxidant mixing while distributing the pressure drop across multiple discharge locations, preventing excessive pressure loss at any single point.
3Manufacturing precision
If a complex fuel injector geometry is used to improve mixing, then fuel/oxidant mixing quality increases, but manufacturing cost and complexity increase
Solution Approach 1:
The patent utilizes spheroidality (curvature) by implementing an undulating trailing edge geometry with specific curvature characteristics. The trailing edge features a defined curvature radius that varies along its length, creating natural vortices through the curved flow path. This curvature-based design achieves complex three-dimensional flow patterns and intense mixing without requiring additional mechanical components, internal passages, or assembly steps, thereby maintaining manufacturing simplicity while delivering superior mixing performance.
4Productivity
If the fuel discharge means is arranged to maximize vortex utilization, then mixing intensity increases, but the device complexity and manufacturing cost increase
Solution Approach 1:
The patent applies universality by designing the undulating trailing edge geometry to serve multiple functions simultaneously: it generates vortices for fuel/oxidant mixing, defines the flow direction, creates the necessary pressure distribution, and provides structural support for mounting the fuel discharge means. This multi-functional geometry eliminates the need for separate mixing devices, flow control elements, or additional structural components, achieving high mixing intensity through a single integrated structure that is relatively simple to manufacture.
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
Enhances fuel/oxidant mixing quality, maintains low burner pressure drop, and reduces NOx emissions and flashback risks, while simplifying manufacturing and enabling efficient dual-fuel operation by generating small vortices and additional shear forces for improved fuel distribution.
Implementation Method 1
At the trailing edge, flows having opposite velocity components across the main flow direction meet and intermingle, and develop vortices propagating downstream from the trailing edge
Implementation Method 2
the trailing edge, when seen parallel to the streamwise direction, undulates along a trailing edge mean line and, along its extent, deviates in opposite directions from said mean line and further comprises at least one inflection point along its extent
Implementation Method 3
provides superior mixing quality for dual-fuel combustors, wherein the injection location may be optimized for the respective type of fuel
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
A fuel injector device (1) comprises a body, said body comprising a leading edge (11) and a trailing edge (12) and defining a streamwise direction (3) from the leading edge to the trailing edge. The fuel injector device body further comprises a first surface (101) and a second surface (102) opposite the first surface, each of said surfaces extending between and comprising the leading edge (11) and the trailing edge (12), and said surfaces conjoining each other at the leading edge and the trailing edge. The trailing edge (12), when seen in the streamwise direction, undulates along a trailing edge mean line (13) and, along its extent, deviates in opposite directions from said mean line and further comprises at least one inflection point (14) along its extent. The fuel injector device further comprises at least one first internal fuel supply means and at least one first fuel discharge duct fluidly connecting the at least one first internal fuel supply means with a first fuel discharge means (15) opening out to the exterior of the injector device, wherein at least one first fuel discharge duct terminates at a first fuel discharge means arranged at the trailing edge. At least one first fuel discharge means (15) is arranged at the trailing edge (12) between two trailing edge inflection points (14).