Underplatform Damping Members for Turbocharger Blade Vibration
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Solution Overview
Problem
Turbocharger turbine blades experience high cycle fatigue-induced failures due to high vibratory stresses caused by low per revolution aerodynamic drivers, which existing technologies fail to effectively mitigate across broad operating speed ranges.
Innovation Solution
The introduction of damping members, specifically designed to fit between the rotor disk and the shoulders of neighboring blades in a turbocharger assembly, which engage under surfaces of the platforms to dissipate energy and reduce vibrations through friction damping, thereby reducing the dependence on dovetail fits and mitigating high cycle fatigue failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If damping members are added to reduce blade vibrations, then blade life is extended, but device complexity increases
Solution Approach 1:
A damping member is introduced as an intermediary element between the rotor disk and the blade platform. This damping member engages with the under surface of the blade platform and the rotor disk to provide vibration damping without requiring changes to the blade dovetail fit or platform structure. The damping member acts as a mediator that absorbs vibratory energy while maintaining the existing blade attachment geometry.
Solution Approach 2:
The vibration damping function is separated from the blade attachment function. Instead of relying solely on the dovetail fit to provide both mechanical attachment and vibration damping, the solution segments these functions by adding a dedicated damping member that provides vibration damping while the dovetail fit maintains mechanical attachment. This segmentation allows each component to optimize its specific function.
2Ease of manufacture
If reliance on dovetail fits for damping is increased, then manufacturing is simpler, but manufacturing precision requirements increase due to tolerance sensitivity
Solution Approach 1:
The damping member serves as an intermediary that reduces the sensitivity of the vibration damping performance to manufacturing tolerances. By introducing this dedicated damping element, the system becomes less dependent on the precise fit of the dovetail interface, allowing for more relaxed manufacturing tolerances while maintaining effective vibration damping.
Solution Approach 2:
The damping member provides beforehand cushioning by being pre-installed in the rotor disk to engage with the blade platform. This pre-positioned damping element cushions the blade platform from vibratory forces before they can cause damage, reducing the need for extremely precise dovetail fits to achieve adequate damping performance.
3Reliability
If external dampers are added to mitigate vibrations, then blade fatigue failures are reduced, but device complexity and assembly steps increase
Solution Approach 1:
The vibration mitigation function is segmented from the blade attachment system by introducing a separate damping member. This allows the dovetail fit to focus on mechanical attachment while the dedicated damping member handles vibration mitigation, improving reliability without requiring the attachment system to perform dual functions.
Solution Approach 2:
The damping member is designed to be self-contained and self-sufficient in providing vibration damping. It requires no external power source, control systems, or active components - simply its presence and engagement with the blade platform and rotor disk provides passive vibration mitigation, reducing blade fatigue failures without adding complex active systems.
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 damping members significantly reduce blade vibrations, extending the useful life of turbine blades by dissipating energy through friction and reducing relative movements between adjacent blades, thus addressing the issue of high cycle fatigue and vibratory stresses across various operating speeds.
Implementation Method 1
The body is configured to dampen vibrations of the blades during rotation of the blades and the rotor disk by engaging under surfaces of the shoulders of the platforms that oppose the rotor disk of at least one of the blades
Data Source
AI summary
Damping members for turbocharger assemblies, methods for providing turbocharger assemblies, and turbocharger assemblies are described herein. The damping members include bodies having shapes to fit between a recess extending into a rotor disk of a turbocharger and laterally protruding shoulders of platforms in neighboring blades of the turbocharger. The bodies dampen vibrations of the blades during rotation of the blades. The damping members may include a variety of shapes, such as a sheet, a wedge, a tapered pin, a cylindrical pin, a bent sheet, or another shape.