Blade Outer Air Seal Attachment Block Design
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Solution Overview
Problem
Existing gas turbine engines face challenges in effectively mounting blade outer air seal assemblies due to the complexity of ensuring proper alignment and secure attachment of these seals radially outward of the turbine blades.
Innovation Solution
A method and structure for assembling blade outer air seal assemblies in a gas turbine engine, utilizing a support system with forward and aft hooks on an attachment block that can be easily aligned and secured onto a static casing, with wedge seals and feather seals to prevent rotation and axial movement, allowing for a full hoop support that facilitates easy assembly and secure positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If blade outer air seal assemblies are mounted radially outward of turbine blades, then sealing effectiveness is improved, but assembly complexity and mounting difficulty increase
Solution Approach 1:
The air seal assembly is divided into modular components including multiple air seal segments (204), wedge seals (208), and feather seals (210) that can be assembled and installed separately. This segmentation reduces overall assembly complexity while maintaining sealing effectiveness at the blade outer diameter.
Solution Approach 2:
Air seal segments and associated seals are pre-assembled into a complete assembly unit before installation on the engine. The preliminary assembly includes positioning features and alignment elements that simplify the final mounting process, reducing on-site assembly complexity.
2Strength
If traditional mounting methods are used for blade outer air seals, then structural support is provided, but alignment precision and mounting time are adversely affected
Solution Approach 1:
The air seal segments are provided with asymmetric positioning features including offset lugs (206) and corresponding receptacles that provide self-alignment during installation. This asymmetric design ensures precise radial and axial positioning without requiring complex alignment procedures.
Solution Approach 2:
Attachment blocks (202) serve as intermediary components between the air seal segments and the engine structure. These blocks provide pre-formed mounting interfaces and alignment features that simplify the connection process while ensuring precise positioning of the air seals relative to the turbine blades.
3Reliability
If secure attachment of air seals is ensured, then sealing reliability is improved, but assembly time and operational efficiency are reduced
Solution Approach 1:
The attachment system is segmented into discrete, pre-fabricated components including attachment blocks with integrated mounting features. This allows the air seal assembly to be prepared independently and installed as a unit, improving assembly efficiency while maintaining secure attachment through multiple localized connection points.
Solution Approach 2:
All attachment features, including hooks, lugs, and alignment elements, are pre-positioned and pre-assembled before engine installation. This preliminary configuration eliminates time-consuming on-site adjustments and ensures secure attachment from the first installation, improving both reliability and productivity.
Data Source
Figure 1
Figure 2
Figure 3~5B
AI summary
A gas turbine engine (20) includes a compressor section (24) and a turbine section (28). The turbine section (28) includes at least one rotor and at least one blade (102) extending radially outwardly from the rotor to a radially outer tip (103). A blade outer air seal (104;162;170) is positioned radially outwardly of the radially outer tip (103) of the blade (102). The blade outer air seal (104;162;170) has forward and aft hooks (106,108). The forward and aft hooks (106,108) are supported on forward and aft seal hooks (112,114) of an attachment block (110). The attachment block (110) has a forward case mount hook (116) and an aft case mount hook (120). The attachment block (110) is supported on a forward case hook (118) and an aft case hook (122) of a static casing (117) within the engine (20). The forward case mount hook (116) and the aft case mount hook (120) on the attachment block (110) face in a first common axial direction. The forward case hook (118) and the aft case hook (122) face in a second common axial direction which is opposed to the common axial direction. A method is also disclosed.