Fuel Modulation Valve Combustion Stability Control
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Solution Overview
Problem
Combustion instability in gas turbine engines, characterized by high amplitude pressure oscillations, diminishes engine performance and can damage hardware components, and existing passive and active control methods are costly or limited in effectiveness.
Innovation Solution
A method and system for actively controlling combustion stability in gas turbine engines using a controller that determines environmental and operating conditions causing instability, and adjusts fuel modulation frequency and amplitude through interfaced sensors and valves to counteract instability, with the ability to monitor and adapt to changing conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If passive control methods are used to correct combustion instability, then combustion stability is improved, but device complexity and cost increase
Solution Approach 1:
The patent applies mechanical vibration by using a valve to generate fuel flow pulsations at specific frequencies that counteract combustion instability. The valve mechanically modulates the fuel flow to create pressure oscillations that are out of phase with the unstable combustion oscillations, thereby damping them and stabilizing combustion without requiring complex control systems.
Solution Approach 2:
The patent employs periodic action by pulsing the fuel flow at predetermined frequencies that match or are related to the combustion instability frequency. This periodic modulation of fuel flow creates a stabilizing effect through constructive and destructive interference with the unstable pressure oscillations, providing simple and effective combustion stability control.
2Reliability
If active control methods are used to correct combustion instability, then combustion stability is improved, but device complexity and cost increase
Solution Approach 1:
The valve-based active control system generates mechanical vibrations in the fuel flow that actively counteract combustion instability. By modulating the fuel flow at frequencies related to the instability, the system creates damping effects that stabilize combustion while maintaining relatively simple device architecture compared to other active control methods.
Solution Approach 2:
The patent changes the frequency and amplitude parameters of the fuel flow pulsations to optimize combustion stability control. By adjusting these parameters based on operating conditions, the system can effectively control combustion instability across different engine regimes while maintaining a simple valve-based implementation.
3Reliability
If high frequency valve operation is used to provide fuel pulsations, then combustion stability is improved, but device complexity increases
Solution Approach 1:
The valve is designed to operate at high frequencies to generate fuel pulsations that stabilize combustion. The mechanical vibration principle allows the valve to effectively modulate fuel flow at these high frequencies, creating the necessary pressure oscillations for stability control without requiring overly complex valve mechanisms.
Solution Approach 2:
The valve performs periodic opening and closing actions at high frequencies to create fuel pulsations. This periodic action, when properly designed, can achieve combustion stability control at high frequencies while maintaining relatively simple valve construction by leveraging the periodic nature of the modulation to achieve the desired stabilizing effect.
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 reduces combustion instability by pulsing fuel flow at optimal frequencies and amplitudes, minimizing pressure wave amplitudes and preventing damage to engine components, while being cost-effective and adaptable to varying conditions.
Implementation Method 1
Combustion instability is generally understood as high amplitude pressure oscillations that occur as a result of the turbulent nature of the combustion process
Implementation Method 2
when the combustion heat release becomes in phase with and reinforces acoustic pressure waves, a thermo-acoustic instability results
Data Source
AI summary
A method of combustion stability control for a gas turbine engine is provided, and includes the steps of receiving by a stability controller, information regarding environmental and operating conditions, and comparing the environmental and operating conditions to pre-programmed information to determine if a likelihood of combustion instability exists. The method further includes the steps of determining optimal fuel modulation frequency and amplitude for the environmental condition to reduce combustion instability, if a likelihood of combustion instability exists, and actuating at least one fuel modulation valve to, at the optimal fuel modulation frequency and amplitude, reduce combustion instability, if a likelihood of combustion instability exists. Systems for modulating fuel flow are also provided.