Gas Turbine Blade Outer Air Seal Support Assembly
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Solution Overview
Problem
The efficiency of gas turbine engines is reduced due to leakage around turbine blades, which can lead to undesirable rubbing when the rotating blade and blade outer air seal respond differently to loads, necessitating control of the clearance between them.
Innovation Solution
A support assembly for the blade outer air seal includes an inner support with a C-shaped cross-section and a cover plate that encloses a cavity, featuring a rail and groove system for alignment and thermal growth matching, ensuring consistent radial growth and preventing axial movement, thus maintaining optimal clearance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the blade outer air seal is held radially outboard from the rotating blade via connections on the case or support structure, then the seal can be positioned to prevent leakage, but the tip clearance may be reduced and the blade may rub on the seal due to different radial response rates
Solution Approach 1:
The support assembly allows the blade outer air seal to move axially relative to the blade through a movable connection mechanism. This dynamic adjustment capability enables the seal to maintain optimal clearance and prevent rubbing while still achieving the desired radial positioning for leakage prevention.
Solution Approach 2:
The invention changes the axial position parameter of the blade outer air seal relative to the blade through the movable connection mechanism. This parameter adjustment allows the seal to maintain proper clearance under varying operating conditions while preventing blade rubbing.
2Productivity
If the blade outer air seal is positioned to prevent leakage, then engine efficiency improves, but the clearance control becomes critical to prevent rubbing under load variations
Solution Approach 1:
The movable connection mechanism provides dynamic adjustment of the seal's axial position, allowing the system to adapt to load variations and maintain optimal clearance without requiring extremely tight manufacturing tolerances on the static clearance dimension.
Solution Approach 2:
The support assembly enables the blade outer air seal to self-adjust its axial position relative to the blade through the movable connection, automatically maintaining proper clearance under varying operating conditions without external intervention.
3Speed
If the rotating blade and blade outer air seal respond radially at different rates due to loads, then the tip clearance is reduced, but this creates undesirable rubbing contact
Solution Approach 1:
The movable connection mechanism allows the blade outer air seal to move axially in response to radial load variations, decoupling the seal's radial response from the blade's radial response. This dynamic movement prevents the seal from contacting the blade during transient conditions while maintaining proper clearance.
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 solution effectively maintains optimal clearance between the blade and the blade outer air seal, enhancing the efficiency of the gas turbine engine by preventing rubbing and ensuring consistent thermal growth, thereby improving engine performance.
Implementation Method 1
ensuring consistent radial growth and preventing axial movement
Implementation Method 2
rail and groove system for alignment and thermal growth matching
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A support assembly (100) for a gas turbine engine includes at least one inner support (104) that extends about a circumferential axis and defines a cavity (126) for receiving a control ring (106). At least one cover plate (108) is attached to at least one inner support (104) to enclose the cavity (126). At least one of the inner support (104) and the cover plate (108) includes a rail (152) and the other of the inner support (104) and the cover plate (108) includes a groove (142) for engaging the rail (152).