Circumferential Stop Ring Seal for Turbine Exhaust Leakage
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Solution Overview
Problem
Existing sealing arrangements in gas turbine engines, such as finger seals, become inefficient and fatigued when sealing across lengthy distances, leading to leakage of exhaust gases and ingress of cooling air, which reduces engine efficiency.
Innovation Solution
A seal system comprising an annular structural frame, a circumferential ring, and a fairing with a circumferential stop ring that limits rotation and incorporates seal lands and backing plates to engage with seals, ensuring effective sealing between structural components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If finger seals are used to seal across lengthy distances, then sealing coverage is improved, but sealing efficiency deteriorates and fatigue increases
Solution Approach 1:
The circumferential stop ring is divided into multiple segments that can be assembled together to cover lengthy circumferential distances. Each segment contains its own seal, allowing the sealing function to be distributed across multiple independent units rather than relying on a single long-deflection finger seal. This segmentation maintains sealing efficiency while achieving extensive sealing coverage.
Solution Approach 2:
The circumferential stop ring acts as an intermediary component between the fairing and the turbine exhaust case. It provides a dedicated sealing surface (seal land) that the seal can contact, eliminating the need for the seal to bridge long gaps directly between moving and stationary components. The stop ring mediates the sealing function by creating a localized sealing interface.
2Length of stationary object
If finger seals deflect over long distances, then sealing reach is improved, but fatigue resistance deteriorates
Solution Approach 1:
The sealing system is segmented into multiple short-deflection seals distributed around the circumferential stop ring, rather than using one long-deflection seal. Each seal only needs to deflect a short distance to contact the seal land, significantly reducing fatigue accumulation while achieving complete circumferential sealing coverage through the combined action of multiple segments.
Solution Approach 2:
The sealing approach transitions from a single radial deflection dimension to a circumferential distribution dimension. Instead of one seal deflecting radially over a long distance, multiple seals are distributed around the circumference, each deflecting radially over a short distance. The sealing reach is achieved through circumferential arrangement rather than individual seal deflection.
Data Source
AI summary
A turbine seal system comprises an annular structural frame, a circumferential ring, a fairing and a seal. The circumferential ring is joined to the annular structural frame. The fairing is disposed within the annular structural frame and is engaged with the circumferential ring to limit circumferential rotation of the fairing with respect to the annular structural frame. The seal extends between the fairing and the circumferential ring. In one embodiment, the structural component comprises a ring-strut-ring turbine exhaust case.