Composite Slider Seal Assembly for Thermal Growth Mismatch
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Solution Overview
Problem
Existing gas turbine engine seal assemblies experience heavy wear and airflow leakage due to thermal growth mismatch and the metallic nature of the seal plates, leading to increased wear and flow resistance between the core and fan bypass airflow passages.
Innovation Solution
A slider seal assembly with a housing, a seal plate, and a retaining ring, where the seal plate is slideable to compensate for thermal growth mismatch, and a fiber-reinforced composite material is used to reduce contact and wear, along with a low aerodynamic profile to minimize flow loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a metallic seal plate is used to provide sealing between interface parts and the outer casing, then sealing effectiveness is improved, but wear at the contact area increases due to the metallic nature and angled contact
Solution Approach 1:
The seal plate is constructed as a composite structure with a metallic substrate providing structural support and a non-metallic coating layer (such as PTFE, PBI, or other polymer coatings) providing low-friction sealing contact. This composite approach maintains the sealing effectiveness of metal while eliminating the high wear caused by direct metal-to-metal contact between the seal plate and interface parts.
2Stability of the object's composition
If the seal plate is fixed rigidly to the housing, then structural stability is improved, but thermal growth mismatch causes displacement and increased wear under severe temperature differences
Solution Approach 1:
The seal plate is designed with dynamic characteristics that allow it to move or flex in response to thermal expansion and contraction. The seal plate may be mounted with compliance features, flexible mounting, or sliding contacts that enable it to accommodate thermal growth mismatch between the core airflow passage and fan bypass airflow passage components, maintaining sealing performance under severe temperature differences without causing displacement wear.
3Reliability
If a traditional seal assembly with housing and seal plate is used, then sealing function is provided, but flow resistance increases and aerodynamic efficiency decreases
Solution Approach 1:
The seal plate utilizes a thin, flexible sealing surface that can conform to the interface part while maintaining minimal clearance. This flexible seal design provides effective sealing with significantly reduced flow resistance compared to traditional rigid seal assemblies, improving aerodynamic efficiency in the gas turbine engine.
4Manufacturing precision
If the opening of the seal plate is machined at an angle to compensate for curvature of the outer casing, then proper alignment is achieved, but wear at the contact area is exacerbated
Solution Approach 1:
The angled contact issue is resolved by using a non-metallic coating on the seal plate that provides low-friction properties. This allows the seal plate to maintain the necessary angled alignment for proper casing curvature compensation while the coating material resists wear from the sliding contact, extending the service life of interface parts.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The slider seal assembly reduces wear and airflow leakage, maintains sealing efficiency, and minimizes flow resistance by sliding to accommodate thermal expansion, while the composite material and low aerodynamic profile enhance durability and fluid flow.
Implementation Method 1
a fiber-reinforced composite material is used to reduce contact and wear
Implementation Method 2
thermal growth mismatch. This is caused by the severe temperature differences the engine experiences between the core airflow passage and the fan bypass airflow passage, which may cause displacement of the interface parts relative to the seal plates
Data Source
Figure 1
Figure 2~5
Figure 3~4
AI summary
A slider seal assembly (30) for a gas turbine engine, comprising a housing (32) comprising an outer surface (42) and an inner surface (44), and a recessed opening (38) between the inner surface and the outer surface, wherein the inner surface of the housing includes a flat portion configured to match a receiver on an inner wall of a casing of the gas turbine engine; a seal plate (34) received within the recessed opening (38) and moveable relative to the housing (32); and a retaining ring (36) configured to retain the seal plate adjacent the housing, the retaining ring (36) includes a plurality of tabs (54) configured to retain the seal plate adjacent the housing.