Rotor Blade Balancing via Predictive Mass Positioning
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Solution Overview
Problem
Rotating parts with heavier blades face significant out-of-balance problems and weight penalties when conventional balancing methods are applied, particularly in integral bladed discs and rings where individual blades cannot be exchanged.
Innovation Solution
A method involving predicting the masses and moment weights of rotor blades with filled internal cavities, determining their relative positions based on these predictions, and filling the cavities to achieve rotational balance, potentially reducing or eliminating the need for balancing lands and minimizing weight penalties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional balancing methods are applied to rotating parts with heavier blades, then out-of-balance problems are addressed, but weight penalty increases due to adding balancing mass or providing balancing lands
Solution Approach 1:
The invention predicts the masses and moment weights of blades with filled internal cavities before assembly, and determines the relative positions of blades based on these predictions. This preliminary action allows the rotating part to be substantially balanced after assembly without requiring post-assembly balancing lands or additional balancing mass, thus achieving rotational balance while minimizing weight penalty.
2Reliability
If balancing mass is added to correct static unbalance, then centre of mass moves to rotational axis, but weight of component increases
Solution Approach 1:
The method predicts blade masses and moment weights before assembly and determines blade positions based on these predictions. This allows the rotating part to achieve static balance after assembly through proper positioning rather than adding balancing mass, thereby maintaining rotational balance while avoiding weight increase.
3Reliability
If material is removed to correct unbalance, then out-of-balance forces are reduced, but balancing lands must be provided which add to component weight
Solution Approach 1:
The invention determines the relative positions of blades on the hub or ring based on predicted masses and moment weights before assembly. This preliminary positioning enables the rotating part to be substantially balanced after assembly without requiring balancing lands, thus reducing structural complexity while achieving rotational balance.
4Productivity
If pre-assembly predicting and positioning is performed, then post-assembly balancing corrections are reduced, but predicting and measurement time increases
Solution Approach 1:
The method involves determining masses, moment weights, and internal cavity volumes of blades before assembly, and determining relative positions based on predicted masses and moment weights. This preliminary action substantially balances the rotating part after assembly, reducing or eliminating the need for time-consuming post-assembly balancing operations, thereby improving overall balancing efficiency despite the additional predicting time.
Data Source
AI summary
A method is provided of rotationally balancing a rotating part. A rotor hub or ring and a plurality of rotor blades for assembly onto the hub or ring are provided, each blade having an unfilled internal cavity. The respective masses and moment weights of the blades with filled internal cavities are then predicted. Next, the rotor blades are assembled onto the hub or ring to form the rotating part. The relative positions of the assembled blades are determined on the basis of their predicted masses and moment weights with filled internal cavities. The internal cavities of the assembled rotor blades are then filled.