Combustor End Cap Fluid Boundaries for Damping Resonant Frequencies
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Solution Overview
Problem
Combustors face issues with high combustion gas temperatures leading to flashback, increased nitrogen oxide production, and reduced fuel efficiency, while high hydrogen fuel compositions cause vibrations and instability, necessitating a solution to reduce resonant frequencies and enhance thermodynamic efficiency.
Innovation Solution
A system comprising an end cap with a shroud and horizontal barrier to define fuel and air plenums, with fluid boundaries positioned upstream of fuel ports to obstruct working fluid flow and dampen resonant frequencies in combustor tubes, creating disturbance areas that reduce combustion dynamics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If higher combustion gas temperatures are used to improve thermodynamic efficiency, then thermodynamic efficiency is improved, but flashback or flame holding conditions occur causing severe damage to nozzles
Solution Approach 1:
The end cap is segmented into multiple functional zones: a fuel plenum for fuel distribution, an air plenum for cooling air supply, and multiple tubes with individual fuel ports. This segmentation allows independent control of fuel and air flows, enabling higher combustion temperatures while maintaining flashback protection through dedicated cooling channels and controlled fuel-air mixing zones.
2Use of energy by moving object
If higher combustion gas temperatures are used to improve thermodynamic efficiency, then thermodynamic efficiency is improved, but nitrogen oxide production increases
Solution Approach 1:
The combustor segments the combustion process into controlled zones within the tube array, allowing localized fuel injection and staged combustion. This segmentation enables better control of peak temperatures and residence time, reducing nitrogen oxide formation while maintaining overall thermodynamic efficiency through improved heat transfer surfaces.
3Productivity
If high hydrogen fuel composition is used to improve combustion efficiency, then combustion efficiency is improved, but resonant frequencies increase causing vibrations and instability
Solution Approach 1:
The design intentionally incorporates damping features within the tube array and end cap structure to counteract resonant vibrations caused by high-frequency combustion dynamics. The horizontal barrier and tube configurations are positioned to disrupt standing wave patterns, reducing mechanical vibrations and combustion instability while maintaining the benefits of high hydrogen fuel composition for improved combustion efficiency.
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 extends combustor operating conditions, maintains design margins against flashback, and reduces undesirable emissions, while protecting components from damage and improving fuel efficiency across a wide range of operating levels.
Implementation Method 1
high frequencies with high hydrogen fuel composition in the combustor. Increased vibrations in the combustor associated with high frequencies
Implementation Method 2
means for reducing combustion dynamics in the combustor, the means comprising a fluid boundary extending across a first set of the plurality of tubes
Data Source
AI summary
A system for reducing combustion dynamics in a combustor (10) includes an end cap (28) that extends radially across the combustor (10) and includes an upstream surface axially separated from a downstream surface. A combustion chamber (26) is downstream of the end cap (28), and tubes (24) extend from the upstream surface through the downstream surface. Each tube (24) provides fluid communication through the end cap (28) to the combustion chamber (26). The system further includes means for reducing combustion dynamics in the combustor (10). A method for reducing combustion dynamics in a combustor (10) includes flowing a working fluid through tubes (24) that extend axially through an end cap (28) that extends radially across the combustor (10) and obstructing at least a portion of the working fluid flowing through a first set of the tubes.