Perforated Structure Combustor Dynamics Control
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Solution Overview
Problem
Gas turbine systems face challenges in controlling combustion dynamics and modal coupling, leading to unwanted vibratory responses in downstream components due to coherent combustion dynamics at resonant frequencies.
Innovation Solution
The implementation of perforated structures with varying geometries and oxidant port configurations in gas turbine combustors to alter combustion dynamics frequencies, reducing modal coupling and coherence between combustors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If combustors are designed with identical geometries and oxidant port configurations, then manufacturing and operation are simplified, but combustion dynamics frequencies align across combustors causing modal coupling and resonant vibrations in downstream components
Solution Approach 1:
The patent applies local quality by introducing specific variations in oxidant port geometries (such as different diameters, areas, or configurations) in specific combustors rather than uniform changes across all combustors. This localized modification alters the combustion dynamics frequencies of affected combustors to break modal coupling, while leaving other combustors unchanged, thus resolving the contradiction between reducing resonant vibrations and maintaining device simplicity.
2Object-affected harmful factors
If combustor geometries are varied to shift combustion dynamics frequencies away from resonant frequencies, then unwanted vibratory responses are reduced, but manufacturing complexity and design difficulty increase
Solution Approach 1:
The patent applies parameter changes by modifying specific geometric parameters of oxidant ports (such as port diameter, area, or shape) to shift combustion dynamics frequencies away from resonant frequencies of downstream components. This targeted parameter adjustment reduces unwanted vibratory responses while maintaining a systematic approach that can be implemented during manufacturing, balancing the reduction of harmful vibrations with manufacturing feasibility.
3Reliability
If identical combustor designs are used across all combustors, then system simplicity and ease of operation are maintained, but coherent combustion dynamics occur at resonant frequencies causing sympathetic vibratory responses
Solution Approach 1:
The patent applies local quality by introducing specific variations in oxidant port geometries in selected combustors to alter their combustion dynamics frequencies. This localized modification prevents coherent combustion dynamics and sympathetic vibratory responses in downstream components, while the variations are designed to be minimal and systematic, thereby maintaining ease of operation and not requiring complex control strategies for the varied configurations.
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 approach effectively mitigates unwanted vibratory responses by shifting combustion dynamics frequencies away from resonant frequencies, thereby reducing modal coupling and potential stress on turbine components.
Implementation Method 1
a mixture of the fuel and oxidant combusts to generate hot combustion gases
Implementation Method 2
combustion dynamics, which occur when the combustor acoustic oscillations interact with the flame dynamics
Implementation Method 3
have frequencies at or near the natural or resonant frequencies of the components
Implementation Method 4
coherence is a measure of the modal coupling, or combustor-to-combustor acoustic interaction, exhibited by the combustion system
Data Source
AI summary
A system includes a gas turbine engine that includes a first combustor and a second combustor. The first combustor includes a first oxidant flow path and a first perforated structure comprising a first plurality of oxidant ports, wherein the first perforated structure is disposed in the first oxidant flow path. The second combustor includes a second oxidant flow path and a second perforated structure comprising a second plurality of oxidant ports. The second perforated structure is disposed in the second oxidant flow path and the first perforated structure has at least one difference relative to the second perforated structure.