Y-Shaped Joint for Gas Turbine Fan and Compressor Deflection Isolation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In aircraft gas turbine engines, a bird strike or blade-off event causes fan rotor deflection, which is transmitted to the boost stage of the low pressure compressor, affecting tip clearance and engine performance due to their conventional tie on the low pressure spool shaft.
Innovation Solution
A Y-shaped joint with a more rigid annular front leg and a less rigid annular rear leg is used to connect the fan rotor and boost compressor to the shaft, reducing deflection transmissibility and maintaining tip clearance by providing relative flexibility between the two components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the fan rotor and boost compressor are rigidly tied together on the low pressure spool shaft, then structural stability is improved, but deflection transmissibility increases causing tip clearance deterioration
Solution Approach 1:
The joint connecting the fan rotor and boost compressor is segmented into multiple legs (front leg and rear leg) with different rigidity characteristics. This segmentation allows each leg to independently manage different aspects of the connection, providing both structural stability and deflection isolation capabilities.
Solution Approach 2:
Different legs of the joint are designed with different rigidity properties - the front leg is more rigid while the rear leg is less rigid. This local quality differentiation enables the joint to provide structural support where needed while allowing controlled deflection in other areas to maintain tip clearance.
2Strength
If a rigid joint is used to connect fan rotor and boost compressor, then connection strength is improved, but deflection isolation capability deteriorates
Solution Approach 1:
The joint structure incorporates dynamic characteristics by having legs with different rigidity, allowing it to adapt its stiffness response based on the direction and type of load. This dynamic behavior enables the joint to maintain strength under normal operation while providing deflection isolation during abnormal events like bird strikes.
Solution Approach 2:
The multi-leg joint acts as an intermediary element between the fan rotor and boost compressor, mediating the transmission of forces and deflections. The specific configuration of legs with varying rigidity allows it to filter out harmful deflections while transmitting necessary mechanical loads.
3Stability of the object's composition
If the fan rotor deflection is transmitted to the boost compressor, then structural rigidity is improved, but engine performance deteriorates due to tip clearance changes
Solution Approach 1:
The joint design changes the rigidity parameter distribution across different legs, creating a non-uniform stiffness structure. This parameter variation allows the system to maintain overall structural rigidity while locally accommodating deflections that preserve tip clearance and engine performance.
Data Source
Figure 1
Figure 2
AI summary
A gas turbine engine having at least one spool assembly, the at least one spool assembly including a fan rotor (14), a compressor (16) disposed downstream of the fan rotor (14), a turbine (18) and a shaft (12) connecting the fan rotor (14), compressor (16) and turbine (18), a joint (32) affixed to an upstream end (36) of the shaft (12), and including a first link (40) connecting the fan rotor (14) to the shaft (12) and a second link (42) connecting the compressor (16) to the shaft (12), the second link (42) being less rigid then the first link (40). A corresponding method of disassociating a fan rotor deflection from a compressor deflection is also provided.