Reverse-flow Annular Combustor Dome Bifurcation
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Solution Overview
Problem
Gas turbine engines face challenges in reducing NOx emissions and managing temperature characteristics, particularly in rich burn, quick quench, lean burn (RQL) reverse-flow annular combustors, where high temperatures cause thermal stresses and interfere with stoichiometry.
Innovation Solution
The design incorporates a combustor dome that bifurcates airflow into inner and outer liners, with a fuel injector injecting fuel tangentially, quench jets for rapid mixing, and dilution jets to maintain stoichiometric conditions, along with a convergent section to reduce passage height and radial distance between liners, optimizing combustion zones for reduced NOx emissions and temperature control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If increased cooling flows are used to manage high temperatures, then temperature control improves, but the stoichiometry of the RQL combustion process is interfered with
Solution Approach 1:
The combustor is divided into three distinct combustion zones (rich burn zone, quench zone, lean burn zone) with separate air and fuel injection systems for each zone. This segmentation allows independent control of stoichiometry in each zone while managing temperatures through targeted cooling flows in the quench zone without disrupting the overall combustion stoichiometry.
Solution Approach 2:
Different regions of the combustor are assigned different local qualities: the rich burn zone has fuel-rich conditions for initial combustion, the quench zone introduces cooling air to rapidly reduce temperature, and the lean burn zone operates with excess air for complete combustion. Each zone's air-fuel ratio and cooling requirements are optimized independently to resolve the temperature-stoichiometry conflict.
2Object-generated harmful factors
If RQL combustion is implemented to reduce NOx emissions, then emissions decrease, but temperature management becomes more difficult
Solution Approach 1:
The rich burn zone performs preliminary combustion of the fuel-air mixture before the gases enter the quench zone. This preliminary action creates a controlled environment where the majority of combustion occurs under fuel-rich conditions that inherently suppress NOx formation, while the subsequent quench zone rapidly cools the gases to lock in low NOx emissions before they can form in the lean burn zone.
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 effectively minimizes NOx emissions and improves temperature characteristics, enhancing combustion efficiency and durability by maintaining desired stoichiometry and temperature distributions, suitable for various industries including aerospace and electricity generation.
Implementation Method 1
the combustor dome is configured to bifurcate the air flow at the combustor dome into a first stream directed to the inner liner and a second stream directed to the outer liner
Implementation Method 2
a combustor dome forming a combustion chamber with the inner liner and the outer liner. The combustion chamber receives air flow through the inner and outer liners, and the combustor dome is configured to bifurcate the air flow
Implementation Method 3
a fuel injector configured to inject a stream of fuel into the combustion chamber in a tangential direction relative to the engine centerline
Implementation Method 4
a combustor in which the compressed gas is mixed with fuel and burned to produce high-pressure, high-velocity exhaust gas
Data Source
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AI summary
A combustor (160) for a gas turbine engine (140) is provided. The combustor includes an annular inner liner (210); an annular outer liner (212) circumscribing the annular inner liner; and a combustor dome (220) having a first edge (224) coupled to the annular inner liner and a second edge (226) coupled to the annular outer liner, the combustor dome forming a combustion chamber (214) with the annular inner liner and the annular outer liner. The combustion chamber (214) accommodates fluid flow through the annular inner (210) and annular outer liners. (212) The combustion chamber (214)converges in the direction of the air flow to reduce a diameter of the combustion chamber. The combustor dome (220) is configured to bifurcate the air flow at the combustor dome into a first stream directed to the annular inner liner and a second stream directed to the annular outer liner.