Compressor Patch Ring Rabbet Fillet Retention
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Solution Overview
Problem
Turbomachine compressor rotor wheels with certain rotor architectures cannot be repaired using patch rings due to design constraints, leading to potential machine malfunctions from surface defects caused by manufacturing or service wear.
Innovation Solution
A patch ring system where the patch ring is mounted on a rabbet with a radial height greater than or equal to the radial height of a fillet in an opposing rabbet, and optionally staked for retention, to prevent axial movement and ensure secure installation on rotor wheels, allowing for effective repair of damaged compressor stages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of repair
If a patch ring is installed on a rotor wheel with a rabbet, then surface defects can be repaired, but the patch ring may walk off the rabbet during operation causing machine malfunction
Solution Approach 1:
The invention transitions from a two-dimensional rabbet surface to a three-dimensional retention structure by adding a radial component. The patch ring's radial height extends beyond the rabbet into the space above it, creating a dimensional barrier that prevents axial walk-off. This vertical dimension addition secures the patch ring without modifying the original rabbet geometry.
Solution Approach 2:
The invention uses a curved fillet surface at the rabbet's axial-radial intersection to create a geometric interlock. The patch ring's curved outer surface mates with the fillet's curved surface, forming a mechanically interlocked joint that resists axial movement. This curvature-based retention eliminates the need for additional fastening mechanisms.
2Reliability
If the patch ring radial height is increased to prevent walk-off, then retention is improved, but the complexity of the repair system increases
Solution Approach 1:
The patch ring design integrates multiple functions into a single component: the radial height provides retention, the outer surface provides the sealing interface, and the overall geometry maintains structural integrity. This multi-functionality eliminates the need for separate retention features, reducing overall system complexity despite the increased radial dimension.
3Reliability
If a fillet is added to the rabbet to create a retention structure, then manufacturing precision requirements increase, but patch ring security is improved
Solution Approach 1:
The invention modifies the rabbet geometry by adding a fillet with specific radius parameters. This parameter change creates a retention structure that is more tolerant to manufacturing variations. The fillet radius can be optimized to provide adequate retention while accommodating normal machining tolerances, reducing the stringency of precision requirements compared to tighter geometric constraints.
Data Source
AI summary
A compressor has a plurality of stages, and each of the stages includes a wheel. Each wheel is configured to receive one or more rotor blades. The compressor includes a patch ring mounted on a first rotor wheel. The first rotor wheel has a first rabbet machined therein, and the patch ring is located on the first rabbet. A second rotor wheel is located upstream from the first rotor wheel. The second rotor wheel has a second rabbet machined therein, and the second rabbet is configured to be located opposite to the first rabbet. The second rabbet has a second fillet located between axial and radial surfaces of the second rabbet. The patch ring has a radial height greater than or equal to a radial height of the second fillet.