Gas Turbine Combustor Pressure Oscillation Damping via Valve Cycling
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Solution Overview
Problem
Gas turbine engines experience pressure oscillations due to cyclic variations in air and fuel pressures within combustors, which propagate and interfere with gas flow, reducing efficiency and potentially causing compressor stall.
Innovation Solution
A system comprising a fuel injector and a valve controlled by a controller that cycles between open and closed positions at specific frequencies and duty cycles based on measured pressure oscillations, adjusting to uncouple heat of release pressure oscillations from combustor pressure oscillations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If continuous fuel flow is provided to the combustor, then stable combustion is maintained, but pressure oscillations increase and propagate through the system
Solution Approach 1:
The fuel flow to the combustor is modulated periodically through a valve that cycles between open and closed positions. This periodic fuel injection creates controlled pressure oscillations at a specific frequency that counteracts and dampens the harmful pressure oscillations propagating through the gas turbine system, while maintaining stable combustion through the controller's regulation of the duty cycle and frequency
2Object-affected harmful factors
If valve cycling frequency is increased to reduce pressure oscillations, then oscillation damping improves, but fuel flow control precision decreases
Solution Approach 1:
The controller receives feedback signals from pressure sensors that measure the magnitude and frequency of pressure oscillations within the combustor. Based on this feedback, the controller dynamically adjusts the valve cycling frequency and duty cycle to optimize oscillation damping while maintaining adequate fuel flow control precision. The system continuously monitors pressure oscillation levels and modifies the valve actuation parameters in real-time to achieve the best compromise between oscillation reduction and fuel flow control
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
Significantly reduces pressure oscillations within the combustor and throughout the gas turbine system, enhancing efficiency and longevity by damping these oscillations.
Implementation Method 1
cycle the valve between the open position and the closed position at a second frequency and a second duty cycle... while the magnitude of the pressure oscillations within the combustor is greater than or equal to the threshold value, and to adjust the second frequency based on a measured frequency of the pressure oscillations
Data Source
AI summary
In one embodiment, a system for reducing pressure oscillations within a gas turbine engine includes at least one fuel injector configured to inject fuel into a combustor. The system also includes a valve fluidly coupled to the at least one fuel injector. The system further includes a controller communicatively coupled to the valve. The controller is configured to cycle the valve between an open position and a closed position at a first frequency and a first duty cycle while a magnitude of pressure oscillations within the combustor is less than a threshold value, to cycle the valve between the open position and the closed position at a second frequency and a second duty cycle while the magnitude of the pressure oscillations within the combustor is greater than or equal to the threshold value, and to adjust the second frequency based on a measured frequency of the pressure oscillations.