Shape Memory Alloy Rotor Support for Gas Turbine Load Mitigation
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Solution Overview
Problem
Gas turbine engines face challenges with rotor imbalances due to fan blade out events, leading to abnormal unbalanced loads that conventional load reduction devices (LRDs) address by permanently decoupling the fan rotor from the support system, impacting engine performance.
Innovation Solution
A rotor support system incorporating a bearing support flange, frame support flange, fastener, damping component made of super-elastic shape memory alloy, and axial retainer, where the fastener fails under excessive load, allowing the damping component to deform and maintain axial retention between flanges, reducing dynamic loads without permanent decoupling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If support components are sized to provide additional strength to minimize damaging unbalanced loads, then the strength and reliability improve, but the overall weight of the engine increases and efficiency decreases
Solution Approach 1:
The rotor support system transitions from a static rigid connection to a dynamic system with controlled flexibility. The super-elastic damping component provides variable stiffness that adapts to loading conditions, allowing the system to be stiff under normal operation and flexible under abnormal loads, eliminating the need for permanently oversized components
Solution Approach 2:
The system changes the mechanical properties of the damping component through super-elastic phase transformation. Under normal operation, the component maintains high stiffness for efficient support. Under excessive loads, the material undergoes phase transformation to provide flexible load path, reducing peak forces without requiring permanent structural changes
2Force
If a mechanically weakened section (primary fuse) is used to decouple the fan rotor from the fan support system during abnormal events, then the dynamic loads are reduced, but the fan rotor is permanently decoupled and subsequent engine operation is significantly impacted
Solution Approach 1:
The system transitions from permanent decoupling to temporary load reduction. The super-elastic damping component provides a flexible load path during abnormal events, reducing peak forces without permanent damage. After the event, the system automatically returns to its original configuration, maintaining full operational capability
Solution Approach 2:
The system converts the potentially harmful excessive loads into beneficial controlled deformations of the super-elastic damping component. The material's phase transformation during overload conditions dissipates energy and protects critical components, while the automatic recovery converts the deformation into a self-healing mechanism that restores full functionality
3Strength
If the fastener is designed to fail under excessive load to protect the rotor support system, then the system is protected from damage, but permanent decoupling occurs and engine operation is impacted
Solution Approach 1:
The super-elastic damping component serves as an intermediary between the fastener and the rotor support system. It provides a alternative load path that absorbs excessive forces through phase transformation, protecting the fastener from catastrophic failure while maintaining system integrity and operational capability
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 system effectively mitigates rotor imbalances by providing high damping forces and maintaining mechanical connection, reducing engine vibrations and the need for trench fillers, while allowing the bearing support flange to regain its original position, thus enhancing engine stability and efficiency.
Implementation Method 1
The damping component includes a super-elastic shape memory alloy. The damping component is configured to deform from a normal state to a deformed state after the fastener fails.
Implementation Method 2
The damping component includes a super-elastic shape memory alloy
Implementation Method 3
The axial retainer is configured to retain the bearing support flange and the frame support flange within an axial displacement from each other after the fastener fails
Implementation Method 4
A radial gap exists between the bearing support flange and the frame support flange when the damping component is in the normal state
Data Source
AI summary
A rotor support system for a gas turbine engine is disclosed. The rotor support system includes a bearing support flange, a frame support flange proximate to the bearing support flange, a fastener between the bearing support flange and the frame support flange, a damping component, and an axial retainer. The damping component includes a super-elastic shape memory alloy. The fastener is configured to fail when a load on the fastener exceeds a threshold value and the damping component is configured to deform from a normal state to a deformed state after the fastener fails. The axial retainer is configured to retain the bearing support flange and the frame support flange within an axial displacement from each other after the fastener fails. A radial gap exists between the bearing support flange and the frame support flange when the damping component is in the normal state.