Variable Vane Assemblies for Non-Axisymmetric Actuation
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Solution Overview
Problem
Gas turbine engines face aerodynamic instability and vibratory loads due to circumferential nonuniformity in airflow at the inlet, caused by aircraft maneuvers, cross-winds, and steam ingestion, leading to adverse aeromechanical behavior.
Innovation Solution
A variable vane assembly with independently pivotable flap portions and strut portions, actuated by electromechanical actuators, is configured for non-axisymmetric actuation to redistribute airflow uniformly, using a sector-based or individual-vane-based actuation scheme with synchronization bars and dedicated actuators to adjust vane angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional fixed vane assemblies are used, then the structure is simple and reliable, but aerodynamic stability deteriorates under circumferential nonuniform flow conditions
Solution Approach 1:
The patent implements variable vane assemblies where the vanes can dynamically adjust their angles through actuation mechanisms. This allows the vane assembly to adapt to varying flow conditions and attenuate circumferential nonuniformity, improving aerodynamic stability while accepting increased structural complexity
Solution Approach 2:
The vane assembly is divided into multiple independently controllable vane elements rather than a single fixed structure. This segmentation enables differential adjustment of individual vanes to counteract circumferential flow nonuniformity, addressing the stability issue while managing complexity through modular design
2Reliability
If variable vane assemblies with independent actuation are implemented, then aerodynamic stability improves, but device complexity increases
Solution Approach 1:
The patent combines multiple actuation mechanisms into an integrated system that controls various vane elements. By merging the actuation functions and using synchronization mechanisms, the system achieves complex flow control while managing the overall complexity through unified control architecture
Solution Approach 2:
The actuation system is designed to perform multiple functions: adjusting vane angles, synchronizing vane movements, and adapting to different flow conditions. This multi-functionality reduces the need for separate dedicated mechanisms, managing complexity while achieving aerodynamic stability
3Reliability
If non-axisymmetric actuation is used to attenuate circumferential distortion, then flow uniformity improves, but manufacturing complexity increases
Solution Approach 1:
The patent applies different actuation characteristics to different vane elements based on their local requirements for flow control. This local quality approach allows non-axisymmetric actuation patterns to be implemented selectively, achieving flow uniformity while simplifying manufacturing compared to fully complex non-uniform designs
Data Source
AI summary
A variable vane assembly may comprise a first vane and a second vane. The first vane may comprise a first strut portion and a first flap portion. The first flap portion may be configured to pivot relative to the first strut portion. The second vane may comprise a second strut portion and a second flap portion. The second flap portion may be configured to pivot relative to the second strut portion. The first flap may be configured to pivot independently of the second flap.