Gas Turbine Combustor Fuel Split Control for Transient Stability
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Solution Overview
Problem
Conventional methods for controlling gas turbine engine combustion systems struggle with combustion instability during transient conditions, leading to increased emissions, component temperature fluctuations, and structural integrity issues, which are not adequately addressed by existing active modulation and intelligent control systems.
Innovation Solution
A method that dynamically adjusts the pilot fuel split by applying a transient active pilot split offset in addition to a steady state active pilot split offset, allowing for faster changes in fuel distribution during transient conditions while maintaining total fuel quantity, to improve combustion stability and reduce emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional fuel split control methods are used during transient conditions, then steady state emissions are controlled, but combustion instability occurs leading to increased emissions, temperature fluctuations, and pressure variations
Solution Approach 1:
The patent implements dynamic fuel split control that adapts the pilot fuel split percentage based on real-time operating conditions. During transient conditions, the system automatically increases the pilot fuel split above the scheduled value to stabilize combustion, while returning to scheduled values during steady state operation. This dynamic adjustment resolves the contradiction by making the control system responsive to changing conditions rather than static.
Solution Approach 2:
The patent changes the pilot fuel split parameter dynamically based on detected transient conditions. When transients are detected, the pilot fuel split is increased from the scheduled value to a higher value to suppress combustion instability. This parameter change allows the system to maintain low emissions during steady state while achieving combustion stability during transients, resolving the harmful effects contradiction.
2Reliability
If the pilot fuel split is increased to stabilize combustion during transients, then combustion stability improves, but the response time of conventional control systems is too slow to effectively counteract instability
Solution Approach 1:
The patent detects transient conditions early and applies the increased pilot fuel split offset before combustion instability fully develops. By anticipating the need for stabilization and acting preemptively, the system reduces the time required to stabilize combustion compared to reactive control approaches that would wait for instability to manifest.
Solution Approach 2:
The patent implements a feedback mechanism that continuously monitors operating conditions to detect transients. When transients are detected, the system automatically adjusts the pilot fuel split accordingly. This closed-loop feedback control enables faster response times by continuously adapting to changing conditions rather than relying on predetermined schedules alone.
3Reliability
If a fast response control system is implemented to quickly adjust fuel splits during transients, then combustion stability improves, but the system complexity increases
Solution Approach 1:
The patent segments the fuel control system into distinct pilot fuel and main fuel pathways with independent control capabilities. By controlling the pilot fuel split as a separate adjustable parameter, the system can quickly respond to transients without requiring complex reconfiguration of the entire fuel system. This segmentation enables fast response while maintaining manageable system complexity through modular control architecture.
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 reduces the time to stabilize combustion, minimizes pressure fluctuations, and limits emissions during transient events, enhancing the reliability and stability of gas turbine engines by quickly adjusting fuel splits to counteract instability and prevent flame failure.
Implementation Method 1
fuel is introduced within the combustion chamber from multiple injection points using multiple fuel supply lines... Within the combustion chamber a pilot flame and a main flame are distinct although interact as is well known to provide flame stability
Data Source
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AI summary
A method of controlling a combustor of a gas turbine engine, the method comprising the steps supplying a total fuel quantity to the combustor dependent on a load of the gas turbine engine, the total fuel quantity is split into a pilot fuel quantity and a main fuel quantity via a scheduled pilot fuel split, the pilot fuel split is the percentage of the pilot fuel quantity of the total fuel quantity, monitoring combustion instability, applying a steady state active pilot split offset to the scheduled pilot fuel split when a predetermined temperature of the combustor is exceeded and/or a predetermined value of combustion instability is exceeded to create a steady state pilot fuel split, monitoring a condition of the gas turbine engine that influences an air / fuel ratio in the combustor, disabling the steady state active pilot split offset when the condition of the gas turbine engine is indicative of a transient condition and when a threshold value of combustion instability is exceeded, and applying a transient active pilot split offset to the steady state pilot fuel split while maintaining the total fuel quantity being supplied at any point in time, the transient active pilot split offset and the steady state active pilot split offset result in a total split offset, the total split offset being greater than the steady state active pilot split offset and the rate of change of the transient active pilot split offset is faster than the rate of change of the steady state active pilot split offset.