Gas Turbine Combustion Oscillation Attenuation via Segmented Fuel Control
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Solution Overview
Problem
Gas turbine engines face instability issues due to combustor thermo-acoustic oscillations, which cause mechanical and thermal fatigue, and existing methods are limited in attenuating multiple frequencies of oscillations across different power settings.
Innovation Solution
A system and method that involves a sensor-controlled manifold and valve system to determine and prevent fuel supply to specific injectors, creating non-homogeneous temperature conditions within the combustion zone to disrupt oscillation propagation by varying fuel delivery based on detected oscillations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fuel introduction point is moved in the injector to change residence time, then oscillations at one frequency can be attenuated, but the system cannot effectively attenuate multiple frequencies of oscillation at different power settings
Solution Approach 1:
The fuel delivery system is segmented into multiple independently controllable fuel injectors. The control system can selectively activate or deactivate specific injectors based on detected oscillation frequencies and power settings, allowing different portions of the combustion zone to be modified to attenuate different oscillation modes.
Solution Approach 2:
The system dynamically adjusts fuel delivery in real-time based on detected oscillation characteristics. The control system monitors combustion oscillations and modifies fuel injection patterns on-the-fly, transitioning from static fuel introduction geometry to dynamic fuel supply control that adapts to changing oscillation frequencies and power settings.
2Reliability
If airflow is introduced through holes around the injector barrel to dilute fuel, then oscillations can be attenuated, but the system is limited in the number of frequencies that can be attenuated
Solution Approach 1:
Instead of a single airflow introduction system, the patent segments the combustion zone into multiple regions controlled by individual or groups of fuel injectors. This segmentation allows different portions of the combustion zone to be independently modified, enabling attenuation of multiple oscillation frequencies simultaneously.
Solution Approach 2:
The system applies local modifications to different portions of the combustion zone by selectively controlling individual fuel injectors. Each injector or group of injectors can be adjusted to create local non-homogeneous temperature conditions that specifically target and attenuate oscillations at particular frequencies or locations.
3Reliability
If fuel supply to injectors is controlled to create non-homogeneous temperature conditions, then combustion oscillations can be attenuated, but the system complexity increases with sensor-controlled manifold and valve mechanisms
Solution Approach 1:
The system employs feedback control where sensors detect combustion oscillations and the control system responds by adjusting fuel delivery to specific injectors. This closed-loop feedback mechanism automates the attenuation process, reducing the need for complex manual control systems while effectively suppressing oscillations across multiple frequencies and power settings.
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
Effectively attenuates combustion oscillations by creating circumferential zones of differing acoustic velocities, reducing mechanical and thermal stress on engine components across various power settings.
Implementation Method 1
combustor thermo-acoustic oscillations... coupling of the heat release and pressure waves
Implementation Method 2
creating circumferential zones of differing acoustic velocities... non-homogenous temperature condition within a combustion zone
Data Source
AI summary
A system and method for modifying the supply of fuel to injectors to attenuate combustion oscillations in a gas turbine engine. The gas turbine engine may comprise a combustor, a plurality of injectors and a manifold. The plurality of injectors may be operable to provide fuel to the combustor. The manifold may be configured to supply fuel to all of the plurality of injectors or to only a portion of the plurality of injectors in reaction to a determination of an existence of combustion oscillations.