Gas Injector Tube with Diffuser Holes for Burner Mixing
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Solution Overview
Problem
Gas turbine engines face challenges in achieving stable combustion and reducing NOx emissions due to lean premixed combustion, which is inherently less stable and sensitive to equivalence ratio fluctuations, leading to unsteady heat release and thermo-acoustic instabilities.
Innovation Solution
The burner design incorporates a gas injector with a tube featuring circular or helical V-formed grooves and diffuser holes at the bottom, which enhances fuel-air mixing by introducing fuel into a vortex, combined with a pilot combustor that supplies heat and free radicals to a main lean premixed swirl, stabilizing combustion through a strong recirculation zone and multi-quarl arrangement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If lean premixed combustion is used to reduce NOx emissions, then NOx emissions are reduced, but combustion stability deteriorates
Solution Approach 1:
The combustion process is divided into two distinct zones: a pilot combustion zone with richer mixture for stable ignition and a main combustion zone with leaner mixture for low NOx emissions. This segmentation allows each zone to operate under optimal conditions, resolving the contradiction between stability and emissions reduction.
Solution Approach 2:
Different equivalence ratios are applied to different spatial locations within the burner. The pilot zone uses a richer mixture (higher equivalence ratio) for stability, while the main zone uses a leaner mixture (lower equivalence ratio) for emissions reduction. This local differentiation allows simultaneous optimization of both stability and emissions.
2Object-generated harmful factors
If more air is added to reduce flame temperature, then NOx emissions are reduced, but combustion stability deteriorates
Solution Approach 1:
The air-fuel mixture is segmented into two regions with different air-to-fuel ratios. The pilot zone uses a richer mixture with less air for stable combustion, while the main zone uses a leaner mixture with more air for low temperature combustion and reduced NOx emissions.
Solution Approach 2:
The pilot combustion zone acts as an intermediary that produces stable flames and hot gases, which then serve as ignition sources for the main combustion zone. This intermediary pilot flame enables the main zone to operate at lean conditions without compromising overall stability.
3Productivity
If premixed combustion is used, then mixing efficiency is improved, but flame stability deteriorates
Solution Approach 1:
The combustion system is segmented into a pilot zone with intense premixed combustion for efficient mixing and a main zone that utilizes the stable flames from the pilot. This segmentation allows the benefits of efficient premixed combustion while maintaining overall flame stability through the pilot's stabilizing influence.
Solution Approach 2:
The equivalence ratio parameter is changed between the two zones: the pilot zone operates with a richer mixture (higher equivalence ratio) that promotes stability, while the main zone operates with a leaner mixture (lower equivalence ratio) that maximizes mixing efficiency and emissions reduction.
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 achieves stable ignition and combustion at all engine load conditions, significantly reducing emissions by maintaining a stable flame front and efficient combustion, even at low temperatures, while minimizing thermal loading and mechanical integrity issues.
Implementation Method 1
introducing fuel into a vortex
Implementation Method 2
enhancing the turbulence of the flow of fuel
Implementation Method 3
supplying heat and high concentration of free radicals from a pilot combustor exhaust to a main flame
Implementation Method 4
reverse flow returns heat and free radicals back to the incoming un-burnt fuel and air mixture
Data Source
Figure 1
Figure 2
Figure 3~4a
AI summary
The invention relates to a gas injector for injecting fuel into a burner for a gas turbine engine. It is an object of the present invention to improve the mixing efficiency of air and fuel to further enhance the efficiency of a burner. According to the invention the gas injector comprises a burner (1) provided with a quarl (4a, 4b, 4c), which is circumferenting a combustion room, at least a first channel (10, 11) emerging into the combustion room for providing the combustion room with air (12) mixed with fuel (14); a swirler (3) for mixing the air (12) and the fuel (14) located at the inlet of said channel (10, 11); at least one tube (15) for the provision of fuel (14) at an inlet (13) of at least one channel (10, 11), wherein said tube (15) is provided with a plurality of diffuser holes (15A) distributed along the tube (15) acting as gas injectors for effectively distributing fuel (14) in a flow of air passing through said channel (10, 11).