Variable Fan Inlet Guide Vane Inner Diameter Actuation
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Solution Overview
Problem
Conventional turbofan engines have a complicated elongated structure due to axial flow, which complicates packaging and high bypass ratio engines lack variable fan inlet guide vanes, affecting engine stability and starting power requirements.
Innovation Solution
A turbine engine with a plurality of variable fan inlet guide vanes actuated from the inner diameter, using a unison ring and torque rod system to control flap positions, reducing the need for an outer diameter unison ring and providing improved stability and lower starting power requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If variable fan inlet guide vanes are actuated from the outer diameter using a unison ring, then the flaps can be controlled to pivot uniformly, but the unison ring would be very heavy and would deflect between the actuator contact point and the diametrically opposite flap, reducing actuation uniformity
Solution Approach 1:
The patent inverts the conventional actuation approach by mounting the unison ring at the inner diameter of the fan inlet guide vanes instead of the outer diameter. This inversion reduces the unison ring's weight and eliminates deflection issues while maintaining uniform flap actuation through the torque rod mechanism that pivots flaps about their leading edges.
Solution Approach 2:
The patent changes the spatial dimension of actuation from outer diameter to inner diameter, effectively moving the actuation point from the periphery to the center. This dimensional change reduces the moment arm and associated deflection, while the torque rod mechanism translates this central actuation into effective flap control.
2Reliability
If variable fan inlet guide vanes are included in high bypass ratio turbine engines, then engine stability is improved and starting power requirements are reduced, but the device complexity and structural complications increase
Solution Approach 1:
The patent segments the fan inlet guide vane system into modular components: individual flaps mounted on separate support structures, each with its own torque rod actuation mechanism. This segmentation allows for simplified assembly and maintenance while achieving the desired engine stability and reduced starting power requirements.
Solution Approach 2:
The unison ring mounted at the inner diameter serves multiple functions: it coordinates the actuation of all fan inlet guide vanes simultaneously, reduces the overall system weight compared to outer diameter actuation, and eliminates deflection issues. This multi-functionality addresses both engine stability requirements and structural simplification.
Data Source
AI summary
A turbine engine includes a plurality of variable fan inlet guide vanes. Where the turbine engine is a tip turbine engine, the variable fan inlet guide vanes permit the ability to control engine stability even though the fan-turbine rotor assembly is directly coupled to the axial compressor at a fixed rate. The fan inlet guide vanes may be actuated from an inner diameter of the fan inlet guide vanes.