Turbine Engine Rotor Blade Sweeps for Vibration Reduction
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Solution Overview
Problem
Existing turbine engine rotor blades experience uniform vibratory modes that lead to high levels of vibration, which can cause structural damage and inefficiencies.
Innovation Solution
Implementing mistuning in rotor blades through blade sweeps in the axial and/or circumferential directions without material addition or removal, disrupting the uniform vibratory mode and reducing overall vibration levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If uniform rotor blades are used, then manufacturing is simpler, but vibration levels increase causing structural damage
Solution Approach 1:
The patent applies asymmetry by introducing blade sweeps at different angles for adjacent rotor blades. Specifically, first rotor blades have a first sweep angle while second rotor blades have a second sweep angle that differs from the first. This asymmetric configuration disrupts the uniform vibratory modes that occur with identical blades, thereby reducing vibration levels and preventing structural damage while maintaining manufacturing feasibility through controlled geometric variations.
Solution Approach 2:
The patent implements local quality by varying the sweep angle specifically at the blade tips rather than uniformly across the entire blade structure. The sweep is applied locally to the outer portion of the rotor blades, creating a localized geometric difference that affects vibratory characteristics without requiring complete redesign of the entire blade. This approach reduces vibration while minimizing impact on overall blade performance and manufacturing complexity.
2Object-affected harmful factors
If blade sweeps are implemented to reduce vibration, then vibration levels decrease, but blade geometry complexity increases
Solution Approach 1:
The patent applies partial action by implementing blade sweeps only on a portion of the rotor blades rather than all blades. Specifically, a first set of rotor blades has a first sweep angle while a second set has a second sweep angle. This partial differentiation is sufficient to disrupt uniform vibratory modes and reduce vibration levels without requiring complete geometric complexity across the entire rotor assembly, thereby balancing vibration reduction with manageable geometry complexity.
3Object-affected harmful factors
If mistuning is applied through material addition or removal, then vibratory response is reduced, but manufacturing complexity and material waste increase
Solution Approach 1:
The patent applies parameter changes by modifying the geometric parameter of blade sweep angle rather than changing material properties or adding/removing material. By varying the sweep angle parameter for different rotor blades, the patent achieves mistuning that reduces vibratory response while avoiding the manufacturing complexity and material waste associated with additive or subtractive material modification approaches. This parameter-based mistuning maintains manufacturing efficiency.
Data Source
AI summary
A rotor blade system for a turbine engine having a longitudinal centerline axis. The rotor blade system includes a rotor configured to rotate about the longitudinal centerline axis and a plurality of rotor blades coupled circumferentially around the rotor, each rotor blade having a leading edge, a trailing edge, a suction side, and a pressure side. At least one rotor blade of the plurality of rotor blades has an axial sweep of both the leading edge and the trailing edge as compared to a base blade of the plurality of rotor blades.