Gas Turbine Fan Blade Retention via Segmented Annular Ring
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing gas turbine engines with variable pitch fan blades face challenges in securely retaining fan blades, particularly in preventing decoupling and disengagement from the fan hub, which can lead to inefficiencies and potential damage during operation.
Innovation Solution
An annular retaining ring configured to limit radially outward movement of the blade receiver, combined with a spring element and a variable pitch mechanism, ensures secure engagement and retention of fan blades by exerting a radially outward force and utilizing a segmented design for ease of assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a variable pitch fan blade configuration is used, then the angle of attack of fan blades can be changed to improve performance, but the risk of blade decoupling and disengagement from the fan hub increases
Solution Approach 1:
The annular retaining ring is divided into multiple circumferential segments that can be independently inserted and positioned. This segmentation allows the retaining ring to flexibly adapt to the variable pitch mechanism while maintaining reliable blade retention, resolving the contradiction between adaptability and reliability
Solution Approach 2:
The annular retaining ring is pre-installed on the fan hub before blade assembly. This preliminary action ensures that the retention structure is already in place and properly positioned, preventing blade decoupling during subsequent variable pitch operations
2Reliability
If a secure retention mechanism is implemented to prevent blade decoupling, then blade retention reliability is improved, but the assembly complexity and difficulty increase
Solution Approach 1:
By segmenting the annular retaining ring into multiple circumferential segments, the complex task of installing a complete annular ring is broken down into simpler, manageable pieces that can be inserted individually through the annular gap, reducing assembly difficulty while maintaining retention reliability
Solution Approach 2:
The retaining ring segments are inserted through an annular gap in the axial dimension, then expand radially to engage with the blade receiver. This dimensional transition from axial insertion to radial engagement simplifies the assembly process while ensuring secure retention
3Reliability
If direct engagement between the retaining ring and blade receiver is used, then blade retention is improved, but wear and friction increase
Solution Approach 1:
A bearing is introduced as an intermediary element between the annular retaining ring and the blade receiver. This bearing mediates the direct engagement, allowing the retaining ring to maintain its retention function while the bearing handles the wear and friction from relative motion
Solution Approach 2:
The spring element applies continuous radial outward force to maintain engagement between the retaining ring and blade receiver. This self-service mechanism ensures constant retention pressure without requiring external actuation, maintaining reliable blade retention
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 effectively prevents fan blade decoupling and disengagement, enhancing operational efficiency and reliability by maintaining consistent blade angle and reducing wear through direct engagement and self-lubricating materials.
Implementation Method 1
a spring element positioned between the fan hub and the blade receiver and biased to exert a radially outward force on the blade receiver
Implementation Method 2
the spring element is self-lubricating
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A gas turbine engine (20) may have a fan section (22) that includes a variable pitch mechanism for changing the pitch of fan blades (105). The gas turbine engine (20) may include a fan hub (110) that is rotatable about an engine central longitudinal axis (A-A') of the gas turbine engine (20) and a blade receiver (120) that is for holding a fan blade (105) and that is rotatably coupled to the fan hub (110) and may be rotatable about a radial axis of the gas turbine engine (20). The gas turbine engine (20) may include a spring element (130) disposed between the fan hub (110) and the blade receiver (120) to bias the blade receiver (120) radially outward and an annular retaining ring (140) may be disposed around the radial axis and between the fan hub (110) and the blade receiver (120) to limit radially outward movement of the blade receiver (120) to prevent the blade receiver (120) from decoupling and disengaging from the fan hub (110).