Pivoting Vane Fan Case Plenum for Gas Turbine Stall Margin
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Solution Overview
Problem
Gas turbine engines experience high distortion due to pressure gradients and swirl, leading to engine stall and undesirable aeromechanical behavior, making it challenging to maintain efficiency and flight envelope while addressing stall conditions.
Innovation Solution
A fan case assembly with pivotable vanes and a control unit that adjusts the vanes' position in response to preselected operating conditions, such as aircraft maneuvers and sensor measurements, to control fluid communication between the gas path and a plenum, minimizing the negative effects of pressure and swirl distortions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the fan operates in embedded gas turbine engine applications, then the engine can be integrated into the aircraft structure, but high distortion in the form of pressure gradients and swirl occurs causing engine stall and undesirable aeromechanical behavior
Solution Approach 1:
The patent applies the dynamics principle by implementing a distortion mitigation system with movable vanes that can dynamically adjust their position based on operating conditions. The vanes are configured to move between different angular positions to actively respond to changing pressure gradients and swirl conditions, thereby maintaining optimal stall margin across various flight regimes while preserving the embedded engine integration benefits
2Reliability
If distortion mitigation systems are added to reduce pressure and swirl distortions, then stall margin is improved, but device complexity increases
Solution Approach 1:
The distortion mitigation system is segmented into multiple independent vanes that can be controlled individually or in groups. Each vane is a discrete component with its own actuation mechanism, allowing the system to manage complexity through modular design. This segmentation enables targeted distortion correction in specific regions of the fan inlet without requiring a complete system redesign
Solution Approach 2:
The system utilizes parameter changes by adjusting the angular position of the vanes to modify flow characteristics. The vanes are actuated to specific angles based on detected distortion levels, changing the flow parameters (pressure distribution, swirl intensity) to minimize adverse effects. This parameter-based control allows the system to maintain simplicity while achieving effective distortion mitigation through precise angular positioning
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
Improves stall margin by allowing for dynamic adjustment of fluid communication, optimizing engine efficiency and performance across various flight conditions without compromising stability.
Implementation Method 1
the plurality of vanes may be pivotably coupled to the case in the plenum to pivot about a pivot axis between a closed position and a fully open position. In the closed position, each vane may cooperate with an inner surface of the case to define the outer boundary of the gas path to block fluid communication between the gas path and the plenum.
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.