Geared Turbofan Architecture With Flexible Support Alignment Control
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Solution Overview
Problem
Traditional gas turbine engines face challenges in efficiently managing the speed difference between the fan and the fan drive turbine, leading to potential misalignment and increased stress on components, which can result in reduced flexibility and increased complexity in design.
Innovation Solution
A geared architecture with a flexible support system, including a deflection limiter and fluid damper passages, is implemented to facilitate a speed change mechanism between the fan and the turbine sections, utilizing a sun gear, carrier, and ring gear configuration with bearings to maintain alignment and reduce stress, while allowing for greater flexibility and compact design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a gear reduction is placed between the fan and the fan drive turbine, then the fan can rotate at slower speeds than the fan drive turbine, but the complexity of the device increases
Solution Approach 1:
The patent employs a planetary gear system where intermediate gears are nested around a sun gear, with a ring gear surrounding the intermediate gears. This nested configuration achieves speed reduction while maintaining a compact structure and managing complexity through hierarchical arrangement of gear components.
Solution Approach 2:
The patent transitions from a single-dimensional direct drive shaft connection to a multi-dimensional planetary gear arrangement, utilizing radial and axial dimensions to organize gear components. This dimensional expansion allows for efficient speed management while distributing mechanical complexity across multiple spatial dimensions.
2Stability of the object's composition
If a rigid support is used for the geared architecture, then alignment is maintained, but flexibility and compact design are reduced
Solution Approach 1:
The patent replaces a static rigid support with a dynamic flexible support that incorporates deflection limiters. These limiters allow the support to adapt its stiffness characteristics, providing rigidity when alignment is needed and flexibility when compact design or movement is required, thus resolving the contradiction between stability and adaptability.
Solution Approach 2:
The flexible support system changes its mechanical parameters (stiffness, deflection characteristics) based on operational requirements. The deflection limiters modify the support's physical state to provide appropriate alignment stability or design flexibility, allowing the system to adapt between rigid and flexible configurations as needed.
3Device complexity
If traditional speed management is used without a geared architecture, then the design is simpler, but stress and misalignment increase
Solution Approach 1:
The patent introduces intermediate gears as mediator components between the sun gear and ring gear. These intermediate elements facilitate smooth power transmission, reduce stress concentrations, and maintain proper alignment between input and output shafts, thereby improving reliability without requiring an overly complex direct coupling mechanism.
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
The solution enables efficient speed management between the fan and turbine sections, reducing stress and misalignment issues, allowing for a more compact and flexible design that enhances the overall performance and efficiency of the gas turbine engine.
Implementation Method 1
at least one seal at least partially defines a fluid damper passage with the axially extending branch and the radial damper housing and a damper fluid is located in the fluid damper passage
Data Source
AI summary
A turbofan engine includes a fan section. A turbine section is in driving engagement with the fan section through a geared architecture. A flexible support supports the geared architecture relative to an engine static structure. A deflection limiter includes at least one of an axially extending branch or a radially extending branch. A flexible output shaft is in driving engagement with the fan section and driven by the geared architecture. A speed change mechanism for a gas turbine engine is also disclosed.