Hemispherical Dome Assembly for Gas Turbine Combustor Stability
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Solution Overview
Problem
Existing gas turbine combustion systems face challenges in controlling the velocity and consistency of the fuel-air mixture entering the combustion liner, leading to variable emissions and instability, particularly due to the difficulty in adjusting airflow and the inefficiencies of diffusion-type nozzles.
Innovation Solution
A hemispherical dome assembly is positioned proximate the inlet of the combustion liner, forming a series of co-axial passageways with controlled radial heights to regulate the fuel-air mixture velocity, ensuring it remains within a predetermined range to prevent flashback and maintain stability, utilizing cylindrical geometries for precise machining and control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If diffusion type nozzles are used for fuel-air mixing, then combustor stability is maintained at high temperature, but emissions of NOx and CO increase
Solution Approach 1:
The patent applies preliminary action by premixing fuel and air before combustion in a separate mixing zone. The fuel injector sprays fuel into a mixing zone where it mixes with air from the compressor before entering the combustion zone, preventing direct diffusion combustion and reducing emissions while maintaining stability
Solution Approach 2:
The combustion system is segmented into distinct zones: a mixing zone where fuel and air are premixed, and a separate combustion zone where the premixed fuel-air mixture burns. This segmentation allows optimized conditions for each function, reducing emissions while maintaining combustor stability
2Object-generated harmful factors
If multiple combustion stages are used with fuel staging, then emissions are reduced through premixing, but control of fuel-air premixture injection becomes difficult due to combustor variables
Solution Approach 1:
The patent introduces an intermediary mixing zone that acts as a buffer between the fuel injector and combustion liner. This mixing zone with controlled geometry and flow characteristics stabilizes the fuel-air mixture before injection, making the system less sensitive to combustor variable changes and improving controllability
Solution Approach 2:
The patent controls the mixing zone geometry parameters (length, diameter, inlet/outlet areas) to optimize mixing efficiency and mixture velocity. By adjusting these geometric parameters, the system achieves consistent fuel-air premixture control despite variations in operating conditions
3Device complexity
If air flow to combustor is controlled by size of openings in combustion liner, then system design is simplified, but airflow is not readily adjustable leading to variable mixture velocity
Solution Approach 1:
The patent makes the airflow control dynamic by positioning the mixing zone inlet upstream of the combustion liner inlet, allowing the mixing zone to actively regulate air-fuel mixing and mixture velocity. This dynamic control mechanism enables adjustment of airflow characteristics without changing the combustion liner opening size
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 solution effectively controls the fuel-air mixture velocity, reducing emissions and improving combustor stability by maintaining the mixture within a targeted velocity range, preventing flashback and ensuring efficient combustion.
Implementation Method 1
a hemispherical dome assembly is positioned proximate the inlet of the combustion liner, forming a series of co-axial passageways with controlled radial heights to regulate the fuel-air mixture velocity
Data Source
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AI summary
The present invention discloses a novel apparatus and way for controlling a velocity of a fuel-air mixture entering a gas turbine combustion system. The apparatus comprises a hemispherical dome assembly which directs a fuel-air mixture along a portion of the outer wall of a combustion liner and turns the fuel-air mixture to enter the combustion liner in a manner coaxial to the combustor axis and radially outward of a pilot fuel nozzle so as to regulate the velocity of the fuel-air mixture.