Balanced Seal Runner Structure for Turbine Vibration and Leakage
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Solution Overview
Problem
Gas turbine engines face challenges in maintaining effective circumferential seals and achieving precise trim balancing, particularly in preventing oil leakage and reducing vibrations, due to limitations in existing seal runner designs and balance weight mounting features.
Innovation Solution
The design incorporates a seal runner with a circumferential array of mounting features for balance weights, featuring a metallic substrate with a chromium carbide coating, interference fit, and a hub configuration that maintains sealing section integrity and allows for efficient cooling, along with a method for manufacturing and installing the seal runner and weights to optimize balance and reduce vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a simple metal ring seal runner is used, then the device complexity is reduced, but the sealing performance deteriorates due to coning and runout during operation
Solution Approach 1:
The seal runner is divided into multiple sections: a mounting section with mounting features for balance weights, a sealing section with the cylindrical sealing surface, and hub sections connecting them. This segmentation allows each section to be optimized independently - the mounting section handles balancing while the sealing section maintains cylindrical integrity for reliable sealing.
Solution Approach 2:
Different sections of the seal runner have different local properties - the sealing section is designed with high cylindrical precision and smooth surface finish for sealing, while the mounting section has features for weight attachment. The hub sections have specific geometries to manage stresses and deformations locally, ensuring the sealing surface remains stable.
2Object-affected harmful factors
If trim balance weights are added to the rotor, then vibrations are reduced, but the device complexity increases due to additional mounting features
Solution Approach 1:
The seal runner is merged with the rotor assembly, and balance weight mounting features are integrated directly into the seal runner structure. This combines the sealing function and balancing function into a single component, reducing overall device complexity while still providing vibration reduction capabilities.
Solution Approach 2:
The seal runner serves multiple functions: it provides the sealing surface for preventing oil leakage, acts as a mounting structure for balance weights to reduce vibrations, and maintains structural integrity under operational loads. This multi-functionality reduces the need for separate components.
3Power
If the seal runner is subjected to operational loads, then the engine power is maintained, but the sealing surface deforms causing oil leakage
Solution Approach 1:
The seal runner is pre-loaded and pre-positioned during assembly to account for expected operational deformations. The mounting features for balance weights are designed to apply preliminary balancing forces that counteract anticipated operational imbalances and sealing surface deformations under power loading conditions.
Solution Approach 2:
The seal runner design accounts for dynamic loads during operation. The hub sections and mounting features are designed to flex and redistribute stresses dynamically, allowing the sealing surface to maintain its cylindrical shape even under varying operational loads and speeds.
Data Source
AI summary
A machine has: an outer member; an inner member mounted for rotation about an axis relative to the outer member; and a seal system. The seal system has: a seal housing mounted to the outer member; one or more seal rings held by the seal housing and having an inner diameter surface; and a seal runner mounted to the inner member and having a first outer diameter surface portion contacting or facing the inner diameter surface of the one or more seal rings. The seal runner has a circumferential array of mounting features. One or more weights are mounted to one or more of the mounting features.