Adjustable Fan Track Liner for Distortion Tolerance
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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 existing technologies struggle to mitigate effectively across various flight conditions and maneuvers.
Innovation Solution
A fan case assembly with a plurality of rotatable drums and a control unit that adjusts the position of these drums between closed, partially open, and fully open positions to control fluid communication between the gas path and a plenum, minimizing the negative effects of pressure and swirl distortions by varying airflow distribution in response to preselected operating conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the fan operates under high pressure and swirl distortions, then the engine can maintain high power output, but the engine stall margin decreases and undesirable aeromechanical behavior occurs
Solution Approach 1:
The patent applies the dynamics principle by making the fan blade trailing edges movable rather than fixed. The trailing edges can dynamically adjust their position between extended and retracted states based on real-time distortion measurements, allowing the fan to adapt to varying operating conditions and maintain optimal stall margin across different power output requirements
Solution Approach 2:
The patent implements feedback by using distortion sensors to continuously monitor pressure and swirl distortions in the fan inlet, then feeding this information to a control system that adjusts the trailing edge positions accordingly. This closed-loop control enables the system to respond to changing conditions and maintain reliable operation across the full power range
2Device complexity
If the fan blade trailing edges are fixed, then the structure is simple and reliable, but the ability to mitigate distortion effects is limited
Solution Approach 1:
The patent transitions from fixed to movable trailing edges, applying the dynamics principle to enable adaptation. The trailing edges are equipped with actuators that allow them to change position dynamically, providing the versatility needed to mitigate distortion effects under various operating conditions while maintaining a relatively simple overall structure
3Adaptability or versatility
If the fan operates across a wide range of flight conditions and maneuvers, then the engine versatility is improved, but the distortion effects become more severe and harder to control
Solution Approach 1:
The patent applies dynamics by enabling the trailing edges to move dynamically in response to varying flight conditions. This allows the fan to adapt to a wide range of operating scenarios including different maneuver types, maintaining effective distortion mitigation across the entire operational envelope rather than being optimized for a single condition
Solution Approach 2:
The feedback control system continuously monitors distortion levels and adjusts trailing edge positions accordingly, enabling the fan to maintain effective distortion mitigation across diverse flight conditions and maneuvers. The system learns from sensor data and automatically optimizes its response to each specific operating scenario
Data Source
AI summary
A gas turbine engine includes a fan and a fan case assembly. The fan includes a fan rotor configured to rotate about an axis of the gas turbine engine and a plurality of fan blades coupled to the fan rotor for rotation therewith. The fan case assembly extends circumferentially around the plurality of fan blades radially outward of the plurality of the fan blades.