Gas Turbine Combustor Premixer Nozzle for Flashback Control
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Solution Overview
Problem
Conventional distributed combustion systems cannot efficiently burn fuels with significant hydrogen or high-hydrocarbon content due to flame flashback issues, leading to unstable combustion and increased emissions.
Innovation Solution
A combustor design incorporating a premixer nozzle with converging tubes and dual fuel injection apertures that enhance fuel-air mixing, allowing for stable combustion of fuels with varying compositions, including hydrogen and high-hydrocarbons, by controlling flame propagation and reducing stagnation zones.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If fuel is injected via axial fuel stage in conventional distributed combustion systems, then CO is lowered at low loads and NOx emissions are reduced, but flame flashback occurs when using fuels with significant hydrogen content or high-hydrocarbon content
Solution Approach 1:
The combustor is divided into multiple functional zones: a radial swirler section for initial mixing, a pre-chamber for further mixing, and a combustion chamber for combustion. The axial fuel stage is positioned in the combustion chamber downstream of these mixing zones, allowing fuel injection without creating local stagnation zones that would cause flashback. This segmentation enables safe use of hydrogen-rich fuels while maintaining low NOx emissions.
Solution Approach 2:
The invention transitions from traditional radial fuel injection to axial fuel injection in the combustion chamber. This dimensional change in fuel injection orientation allows the fuel to be introduced in a region where flow patterns prevent flashback, while still achieving the emission reduction benefits of distributed combustion systems.
2Productivity
If premixing is used in distributed combustion systems, then CO is lowered and efficiency is improved, but flame flashback occurs due to local stagnation or recirculation zones
Solution Approach 1:
The mixing and combustion processes are segmented into distinct zones. Premixing occurs in the radial swirler and pre-chamber regions, while the axial fuel stage is positioned downstream in the combustion chamber. This spatial segmentation allows efficient premixing without creating flashback-prone stagnation zones in the fuel injection region.
Solution Approach 2:
Fuel and air are preliminarily mixed in the radial swirler and pre-chamber before reaching the axial fuel stage. This preliminary mixing action prepares the mixture for combustion in a controlled manner, achieving efficiency improvements while the downstream positioning prevents flashback.
3Stability of the object's composition
If conventional radial swirler design is used, then fuel and air mixing is achieved, but stable combustion of hydrogen-rich fuels cannot be maintained due to flashback
Solution Approach 1:
The combustor architecture segments the radial swirler function from the axial fuel stage. The radial swirler provides initial mixing stability, while the axial fuel stage in the combustion chamber provides stable combustion of hydrogen-rich fuels without flashback by positioning fuel injection in a region with favorable flow patterns.
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 design prevents flame flashback while achieving efficient combustion with low emissions, providing stable operation and improved mixing of fuels with air, thus enhancing combustion efficiency and reducing NOx and other pollutants.
Implementation Method 1
compressed air passes in a radially inward and tangential direction to create a swirling fuel and air mixture
Implementation Method 2
Each tube of the array of tubes comprising an inlet, an outlet, a first aperture and a second aperture... a first portion of the air passes through the radial swirler and a second portion of the air passes through the tubes of the array of tubes from inlet to outlet and mixes with the first fuel
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A combustor (36) for a gas turbine, the combustor (36) comprising a combustor axis (44) about which is arranged in flow sequence a radial swirler (40), a pre-chamber (42) and a combustion chamber (38). The radial swirler (40) comprises a base plate (45), an annular array of swirler vanes (46), defining swirler slots (47), arranged around the base plate (45), a main fuel injector (48A, 48B) for injecting a main fuel and a pilot fuel injector (50) for injecting a pilot fuel. The combustor comprises a premixer nozzle (70) located on the combustion chamber (38). The premixer nozzle (70) comprising a housing (78), an array of tubes (80) within the housing (78) and a first fuel gallery (72) for supplying a first fuel (83). Each tube (80) of the array of tubes (80) comprising an inlet (86), an outlet (88), a first aperture (90) and a second aperture (92). The first fuel gallery (72) is arranged to supply the first fuel (83) to the first aperture (90) and / or the second aperture (92). In use, air (34) is supplied to the combustor and a first portion of the air (34A) passes through the radial swirler (40) and a second portion of the air (34B) passes through the tubes (80) of the array of tubes (80) from inlet (86) to outlet (88) and mixes with the first fuel (83) that passes through the first aperture (90) and / or the second aperture (92).