Gas Turbine Fan Static Structure with Angled Vanes
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Solution Overview
Problem
The existing gas turbine engine structures face challenges in managing roll torque reactions and maintaining structural balance as the engine is positioned closer to the wing, which reduces the nacelle and pylon length, necessitating a more efficient distribution of reaction loads and moments.
Innovation Solution
A static structure comprising a ring and hub with angled vane elements and strut members, where the vane elements have axial and tangential inclinations, and strut members are evenly spaced to restrain roll torque and allow differential axial movement, providing a robust connection with six degrees of freedom between the fan casing and core.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the engine is positioned closer to the wing to reduce nacelle and pylon length, then the wing attachment loads are reduced, but the roll torque reactions and structural balance become more challenging to manage
Solution Approach 1:
The patent employs a dynamic structural system where the rear fan case is permitted to rotate relative to the hub along the drive shaft axis. This rotation is restrained by struts that can accommodate differential axial movement, allowing the structure to dynamically adapt to roll torque reactions. The system transitions from a rigid fixed-position structure to one with controlled rotational freedom, resolving the contradiction between compact positioning and structural balance.
Solution Approach 2:
The patent changes the operational parameters of the rear fan case by allowing it to rotate within a controlled range relative to the hub. This parameter change (from fixed to rotatable) enables the structure to better manage roll torque reactions while maintaining the reduced nacelle length configuration. The struts accommodate this parameter change through their ability to restrain differential axial movement.
2Device complexity
If the rear fan case is deleted to allow closer engine placement, then the structure is simplified, but alternative structures must be provided to reconcile reaction loads and moments
Solution Approach 1:
The patent makes the rear fan case serve multiple functions: it maintains its original role in guiding airflow while simultaneously acting as a structural element that can rotate to accommodate roll torque reactions. The struts provide dual functionality by both supporting the rear fan case and restraining differential axial movement. This multi-functionality reduces the need for additional alternative structures while properly managing reaction loads.
Solution Approach 2:
By allowing the rear fan case to rotate relative to the hub, the patent introduces a dynamic element that enables the simplified structure to properly reconcile reaction loads and moments. The rotational freedom, restrained by the struts, allows the system to adapt to varying load conditions without requiring complex alternative support structures.
3Strength
If vane elements are angled with axial lean and tangential inclination, then roll torque is restrained, but the structure becomes more complex
Solution Approach 1:
The patent merges the roll torque restraint function with the existing vane elements that are already part of the engine structure. By angling these existing elements with axial lean and tangential inclination, the patent combines multiple functions into unified components, reducing overall structural complexity while maintaining effective roll torque restraint.
Solution Approach 2:
The patent modifies the geometric parameters of the vane elements by introducing axial lean and tangential inclination angles. These parameter changes enable the vane elements to restrain roll torque while integrating seamlessly with the existing structure, avoiding the need for entirely new complex components.
4Stability of the object's composition
If strut members are used to restrain differential axial movement, then structural stability is improved, but the device complexity increases
Solution Approach 1:
The struts are designed to perform multiple functions: they support the rear fan case, restrain differential axial movement between the hub and rear fan case, and accommodate the rotational movement. By making the struts multi-functional, the patent reduces the need for additional separate components, thereby improving structural stability without proportionally increasing device complexity.
Data Source
AI summary
A static structure is provided such as that used as an engine structure 30 within a gas turbine engine. A structure 30 comprises a hub or core 33 with a concentric ring or casing 32. The hub 33 and casing 32 are secured together through spoke or vane elements 31 which are sloped axially and tangentially relative to a principal axis X-X. In such circumstances any roll torque reaction caused by differentially rotating hub and ring motions is retained by the tangential inclination of the spokes or vanes whilst axial sloping of these spokes or vanes 31 and axially sloping of the struts 34 creates bracing in the direction of the principal axis X-X. In such circumstances essentially robust triangles are formed radially and longitudinally respectively each comprising spokes or vanes 31 and struts 34 secured at axially spaced locations on the hub or core 33.