Corrugated Damper for Gas Turbine Blade Vibration Damping
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Solution Overview
Problem
Gas turbine engine rotor blades experience high vibratory stress and aeroelastic instability due to operational requirements like cross-winds and inlet distortion, necessitating effective damping mechanisms to mitigate these issues.
Innovation Solution
A corrugated sheet metal damper is integrated within the internal cavities of the airfoil, oriented transverse to the blade's leading and trailing edges, which provides damping through frictional contact forces developed under centrifugal load, effectively reducing chordwise and bending mode vibrations by slipping and generating frictional heating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If airfoils are designed to high tolerances to accommodate cross-winds and inlet distortion, then operational reliability is improved, but vibratory stress and aeroelastic instability increase
Solution Approach 1:
A damper is introduced as an intermediary element between the blade structure and the vibratory forces. The damper includes a damping element with friction surfaces that contact each other during blade vibration, converting mechanical vibratory energy into thermal energy through friction, thereby reducing vibratory stress without compromising structural integrity
Solution Approach 2:
The damping element utilizes friction-based energy dissipation by changing the physical state of mechanical energy from kinetic (vibration) to thermal energy. The friction coefficient and contact pressure are controlled to optimize damping effectiveness while maintaining blade performance
2Stability of the object's composition
If damping mechanisms are added to reduce vibratory stress, then aeroelastic stability is improved, but device complexity increases
Solution Approach 1:
The damping element is nested within the hollow airfoil structure, utilizing the existing internal cavity space. The damping element is positioned between the leading edge and trailing edge, fitting within the airfoil's internal geometry without requiring external additions, thus minimizing structural complexity while providing effective damping
Solution Approach 2:
The damping element employs thin friction surfaces that can deform and contact each other during vibration. These thin film-like structures provide effective damping with minimal material usage and structural complexity, allowing the damper to function within the constrained space of the hollow airfoil
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 damper effectively reduces vibratory stress and aeroelastic instability by dissipating energy through frictional heating, ensuring stable operation across various speed ranges.
Implementation Method 1
provides damping through frictional contact forces developed under centrifugal load, effectively reducing chordwise and bending mode vibrations by slipping and generating frictional heating
Implementation Method 2
provides damping through frictional contact forces developed under centrifugal load
Data Source
Figure 1
Figure 2~4
Figure 5~6
AI summary
A blade (44) includes an airfoil portion (64) which defines at least one cavity (74A-74F) with a damper (80) located within the cavity (74A-74F), the damper (80) includes a corrugated surface (80C) which is configured to provide chordwise mode and bending mode damping.