Gas Turbine Blade Flutter Control via Tip Timing
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Solution Overview
Problem
Gas turbine engine blades experience destructive vibrations due to flutter and forced response, leading to potential damage and performance degradation, as existing technologies struggle to effectively control these aero-elastic instabilities.
Innovation Solution
A flutter control system that employs optical tip timing sensors to detect blade vibrations and a controller-actuated nozzle system to inject high-pressure air, altering unsteady pressures and damping flutter by modulating the flow of compressor gases based on sensed vibration data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high-pressure air is injected into the blade row to alter unsteady pressure, then aerodynamic damping increases and flutter is dampened, but device complexity increases due to the nozzle system and control mechanisms
Solution Approach 1:
The system uses optical tip timing sensors to detect blade vibrations and feeds this information back to the controller, which modulates the nozzles in real-time to counteract flutter conditions. This closed-loop feedback mechanism enables effective flutter control while allowing the system to adapt to varying operating conditions.
Solution Approach 2:
The invention employs pneumatic actuation of nozzles that inject high-pressure air into the blade row. By using gas dynamics and pressure modulation rather than mechanical actuation, the system achieves effective flutter control with reduced mechanical complexity and improved reliability.
2Reliability
If optical tip timing sensors and nozzle actuators are added to detect and control flutter, then blade damage is prevented, but manufacturing precision requirements increase
Solution Approach 1:
The system monitors and responds to changes in vibration parameters detected by the optical sensors. By focusing on parameter detection and response rather than requiring extreme manufacturing precision, the system achieves reliable blade protection through adaptive control.
3Reliability
If the nozzle system is continuously actuated to dampen flutter, then vibration amplitude is reduced, but energy consumption increases
Solution Approach 1:
The nozzle system operates in a periodic or pulsed manner rather than continuously. The controller activates nozzles only when flutter conditions are detected by the optical sensors, and modulates them in synchronization with the vibration cycles. This periodic action reduces energy consumption while maintaining effective flutter suppression.
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
The system effectively reduces flutter instability by increasing aerodynamic damping and preventing blade damage, thereby enhancing the operational range and reliability of gas turbine engines.
Implementation Method 1
A plurality of optical tip timing sensors located in a fan case of the turbomachine are configured to sense the passing of blade tips of a fan of the turbomachine
Implementation Method 2
High pressure air off of the compressor is directly injected into the blade row to alter unsteady pressure
Implementation Method 3
A nozzle actuator is operably connected to the controller, such that the nozzle actuator selectively actuates the nozzles directed at the edges of the blades in response to data from the plurality of optical tip timing sensors indicating flutter or near flutter conditions
Data Source
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AI summary
A gas turbine engine includes a central wheel and a plurality of blades that extend outwardly from the central wheel. The gas turbine system includes a flutter control system that is adapted to use blade tip timing to determine blade flutter and to direct high pressure air from the compressor to the fan blade row to alter the surface unsteady pressure so that it is out of phase with the blade motion to reduce or eliminate fan blade flutter.