Asymmetric Rotor Base for Turbomachine Sealing and Coating
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Solution Overview
Problem
Rotors in turbomachines face challenges in maintaining axial and radial clearance-gaps during operation, leading to potential contact between the rotor base and sealing elements, which can cause damage, and existing designs often result in unintentional coating of the rotor arm during maintenance due to insufficient axial width for masking.
Innovation Solution
The rotor base is designed with asymmetrically configured base portions on either side of the sealing fin, having different radial heights and axial extents, allowing for optimal clearance-gap fulfillment and reliable coating masking by preventing contact with the sealing element across all operating conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the axial width of the base portions is increased to provide sufficient supporting surface for coating masks, then coating masking reliability is improved, but the risk of axial contact between the base and sealing element during compressor surge increases
Solution Approach 1:
The base portions are designed with asymmetric radial heights relative to the sealing fin, where the first base portion has a different radial height than the second base portion. This asymmetry allows one base portion to extend further axially to provide adequate mask support while the other base portion is limited in radial height to prevent contact with the sealing element during surge conditions.
Solution Approach 2:
Different regions of the base structure are given different properties: the first base portion has a larger radial height to provide sufficient supporting surface for coating masks, while the second base portion has a smaller radial height to maintain clearance and prevent contact with the sealing element. This local differentiation resolves the contradiction between masking needs and contact prevention.
2Reliability
If the radial height of base portions is increased to prevent contact with sealing elements, then clearance-gap fulfillment is improved, but the supporting surface area for coating masks becomes insufficient
Solution Approach 1:
The asymmetric design allows one base portion to have sufficient radial height for mask support while the other base portion maintains appropriate clearance. This resolves the contradiction by distributing different functional requirements to different locations of the base structure.
Solution Approach 2:
The base is segmented into two distinct base portions with different radial heights. This segmentation allows each portion to be optimized independently for its specific function: one for mask support and one for clearance maintenance, thereby resolving the area vs. clearance contradiction.
3Ease of manufacture
If a symmetric base design is used with equal radial heights on both sides of the sealing fin, then manufacturing simplicity is maintained, but either contact with sealing element or insufficient mask support occurs
Solution Approach 1:
The design deliberately introduces asymmetry into the base portions to simultaneously achieve both manufacturing feasibility and functional requirements. The asymmetric configuration is simple enough to manufacture while providing the necessary differential support for both mask adherence and clearance maintenance.
Data Source
AI summary
A rotor (10) for a turbomachine, in particular for an aircraft engine, having a rotor base body (12), on which at least one sealing fin (14), which is disposed on a base (16), is provided for cooperating with an associated sealing element (20) of the turbomachine; relative to an axial direction of the rotor (10), the base (16) having a base portion (16a) disposed upstream of the sealing fin (14) and a base portion (16b) disposed downstream thereof, for supporting masks during the coating of sealing fins; the upstream base portion (16a) and the downstream base portion (16b) having different radial distances (A1, A2) to a radially outer sealing tip (18) of the sealing fin (14). Also, a turbomachine having at least one such rotor (10).