Movable Closure Plenum for Gas Turbine Stall Margin
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Solution Overview
Problem
Gas turbine engines experience high pressure and swirl distortions, leading to engine stall and undesirable aeromechanical behavior, which complicates maintaining optimal stall margin and efficiency across various flight conditions.
Innovation Solution
A fan case assembly with a movable closure and control unit that adjusts fluid communication between the gas path and a plenum, allowing for alignment of slots with inlet openings to mitigate pressure and swirl distortions by rotating between closed, open, and intermediate positions based on preselected operating conditions and sensor measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the fan operates in embedded gas turbine engine applications, then the engine can be compact and integrated, but the engine experiences high pressure and swirl distortions that cause stall and undesirable aeromechanical behavior
Solution Approach 1:
The patent applies a movable closure that can rotate between different positions (closed, open, intermediate) to dynamically adjust the plenum's fluid communication with the gas path. This dynamic adjustment allows the system to adapt to varying operating conditions and distortion levels, improving stall margin while maintaining compact embedded engine configuration.
Solution Approach 2:
The patent changes the flow distribution parameter by rotating the movable closure to different angular positions. This alters the amount of air directed into the plenum versus the gas path, thereby modifying pressure distribution and reducing swirl distortions that cause stall, while maintaining the compact engine design.
2Reliability
If the movable closure is positioned to allow fluid communication between the gas path and plenum, then pressure and swirl distortions are reduced, but the device complexity increases due to the control unit and actuator mechanisms
Solution Approach 1:
The control unit automatically monitors operating conditions and sensor data to determine the optimal closure position without requiring external manual intervention. The system self-regulates by processing sensor inputs and actuating the closure mechanism accordingly, which manages the complexity through automation rather than requiring multiple separate control systems.
Solution Approach 2:
The movable closure mechanism serves multiple functions: it controls fluid communication between the gas path and plenum, adjusts air distribution to reduce distortions, and can operate at multiple positions (closed, open, intermediate) to handle various operating conditions. This multi-functionality consolidates what would otherwise require separate systems into a single integrated mechanism.
3Adaptability or versatility
If the movable closure rotates to intermediate positions to vary fluid communication, then the system can adapt to different operating conditions, but the manufacturing precision requirements increase
Solution Approach 1:
The system uses a continuously adjustable movable closure that can be positioned at multiple angles rather than fixed discrete positions. This dynamic positioning allows smooth variation of fluid communication to match different operating conditions, and the precision requirements are managed through controlled mechanical rotation rather than requiring extremely tight manufacturing tolerances on each individual position.
Solution Approach 2:
The control unit receives sensor measurements about operating conditions and uses this feedback to determine the optimal closure position. This closed-loop control system compensates for manufacturing variations by adjusting the closure position based on actual operating parameters, thereby achieving adaptability without requiring extremely high manufacturing precision for each fixed position.
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 solution effectively minimizes the negative effects of pressure and swirl distortions, improving stall margin and maintaining engine performance across different flight conditions by dynamically controlling fluid communication and air pressure equalization.
Implementation Method 1
The control unit may minimize negative effects of pressure and swirl distortions in the gas turbine engine to improve stall margin for the gas turbine engine
Data Source
AI summary
A fan case assembly adapted for use with a gas turbine engine includes a case at extends circumferentially at least partway about an axis of the gas turbine engine and a plurality of vanes. The case is formed to define a plenum that extends circumferentially at least partway about the axis. The plurality of vanes are arranged in the plenum and spaced apart circumferentially about the axis to define a plurality of inlet openings in fluid communication with the plenum.