Gas Turbine Rotor Overspeed Protection Assembly
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Solution Overview
Problem
Gas turbine engines face instability and potential rotor overspeed issues due to high shaft failures, which existing methods like blade and vane intermeshing or fuel shutoff may not always be viable, necessitating an alternative control mechanism.
Innovation Solution
A rotor overspeed protection (ROP) assembly featuring an annular blade outer air seal (BOAS) assembly with ROP and BOAS segments, including flanges that interact to control rotor speed by contacting stator vanes, thereby reducing torque and preventing overspeed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If blade and vane intermeshing or fuel shutoff are used to prevent rotor overspeed, then rotor speed control is achieved, but these methods may not be viable options in certain failure scenarios
Solution Approach 1:
The patent introduces a stator flange as an intermediary component between the rotor blades and the stationary structure. This flange acts as a mediator that provides mechanical interference or frictional braking when the rotor overspeeds, offering a reliable protection mechanism that works independently of blade-vane intermeshing or fuel shutoff systems.
2Reliability
If frictional braking from metal to metal contact is used to control rotor speed, then rotor overspeed is prevented, but mechanical wear and potential damage to hardware increases
Solution Approach 1:
The patent uses a stator flange that contacts the rotor blades or hub during overspeed events. This flange is specifically designed as a sacrificial or replaceable component that absorbs the mechanical contact stresses, protecting the more critical rotor and stator structures from direct metal-to-metal damage while still providing the necessary frictional braking effect.
3Force
If a stator flange is positioned to contact rotor components during overspeed, then mechanical braking is provided, but the structural integrity of the stator vane must be maintained
Solution Approach 1:
The patent divides the stator assembly into separate functional components: the stator vane structure that maintains structural integrity and the stator flange that provides the braking interface. This segmentation allows the flange to be optimized for contact and friction operations while the vane structure remains optimized for structural strength and aerodynamic function.
Solution Approach 2:
The stator flange is pre-positioned in a specific location and orientation relative to the rotor components. During normal operation, it remains clear of contact. When overspeed occurs, the flange is already in the correct position to immediately engage and provide braking force, eliminating the need for dynamic positioning during the emergency event.
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 ROP assembly effectively diminishes or prevents rotor overspeed by engaging with stator vanes to reduce torque, providing a reliable protection mechanism for gas turbine engines.
Implementation Method 1
frictional braking from metal to metal contact of rotating and static hardware
Data Source
AI summary
A gas turbine engine may include a rotor overspeed protection (ROP) assembly. The ROP assembly may include an annular blade outer air seal (BOAS) assembly including a ROP segment. The ROP assembly may include a stator vane coupled with the BOAS assembly/. The stator vane may include a stator flange disposed about a forward edge portion of the stator vane. The ROP segment may include a ROP flange extending in an axially aft direction from a main body of the ROP segment toward the stator vane, wherein the ROP flange is disposed radially inward of the stator flange.