Combustor End Cap Diluent Barrier for Flame Stability
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Solution Overview
Problem
Combustors face issues with high combustion gas temperatures leading to flashback, flame holding, and increased nitrogen oxides, while lower temperatures result in reduced chemical reaction rates and increased carbon monoxide and unburned hydrocarbons, and high frequencies cause vibrations and instability, reducing component life and increasing emissions.
Innovation Solution
A system with radially arranged tube bundles in an end cap, featuring a diluent passage and supply to create a diluent barrier between adjacent tube bundles, decoupling flame interaction and reducing combustion dynamics by flowing a diluent through the passage into the combustion chamber.
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 the thermodynamic efficiency is improved, but flashback or flame holding conditions occur causing severe damage to nozzles
Solution Approach 1:
The combustor is divided into multiple individual combustor components, each with its own nozzle and flame holder. This segmentation isolates the high-temperature combustion zones, preventing flashback from propagating across the entire combustor and damaging multiple nozzles simultaneously.
Solution Approach 2:
A diluent barrier is introduced as an intermediary substance between adjacent tube bundles. This diluent barrier acts as a mediator that prevents direct flame interaction and flashback propagation while allowing the high-temperature combustion process to continue efficiently in each zone.
2Use of energy by moving object
If higher combustion gas temperatures are used to improve thermodynamic efficiency, then the thermodynamic efficiency is improved, but nitrogen oxides production increases
Solution Approach 1:
The combustor design creates different local conditions in different zones. By segmenting the combustor and introducing diluent barriers between zones, the local temperature and oxygen concentration are controlled independently, allowing efficient combustion in each zone while limiting NOx formation through localized dilution.
Solution Approach 2:
An inert diluent atmosphere is introduced between adjacent tube bundles to suppress combustion dynamics and reduce nitrogen oxides production. The diluent creates a chemically inert environment that prevents excessive temperature rise and limits the chemical reactions that produce NOx.
3Temperature
If high frequencies are present in the combustor to enable higher operating temperatures, then the operating temperature is improved, but vibrations increase reducing component life
Solution Approach 1:
A diluent barrier is introduced as an intermediary substance between adjacent tube bundles. This diluent barrier acts as a mediator that prevents direct flame interaction and flashback propagation while allowing the high-temperature combustion process to continue efficiently in each zone.
Solution Approach 2:
An inert diluent atmosphere is introduced between adjacent tube bundles to suppress combustion dynamics and reduce nitrogen oxides production. The diluent creates a chemically inert environment that prevents excessive temperature rise and limits the chemical reactions that produce NOx.
4Temperature
If high frequencies are present in the combustor to enable higher operating temperatures, then the operating temperature is improved, but pressure pulses affect flame stability and increase emissions
Solution Approach 1:
The combustor is divided into multiple individual combustor components, each with its own nozzle and flame holder. This segmentation isolates the high-temperature combustion zones, preventing flashback from propagating across the entire combustor and damaging multiple nozzles simultaneously.
Solution Approach 2:
An inert diluent atmosphere is introduced between adjacent tube bundles to suppress combustion dynamics and reduce nitrogen oxides production. The diluent creates a chemically inert environment that prevents excessive temperature rise and limits the chemical reactions that produce NOx.
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 solution enhances thermodynamic efficiency, protects combustor components, and reduces undesirable emissions by stabilizing the combustion process and maintaining design margins across varying operating conditions.
Implementation Method 1
A diluent supply in fluid communication with the first divider provides diluent flow to the first diluent passage in the first divider
Data Source
AI summary
A system for reducing combustion dynamics in a combustor includes an end cap having an upstream surface axially separated from a downstream surface, and tube bundles extend from the upstream surface through the downstream surface. A divider inside a tube bundle defines a diluent passage that extends axially through the downstream surface, and a diluent supply in fluid communication with the divider provides diluent flow to the diluent passage. A method for reducing combustion dynamics in a combustor includes flowing a fuel through tube bundles, flowing a diluent through a diluent passage inside a tube bundle, wherein the diluent passage extends axially through at least a portion of the end cap into a combustion chamber, and forming a diluent barrier in the combustion chamber between the tube bundle and at least one other adjacent tube bundle.