Annular Piston Actuated Blade Tip Clearance Control
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Solution Overview
Problem
Gas turbine engines face challenges in maintaining optimal radial tip clearance between blade tips and shroud assemblies due to varying thermal and operational conditions, leading to potential rubbing issues and reduced engine performance.
Innovation Solution
An active blade tip clearance control system utilizing an annular piston with lift lugs and blade outer air seal segments, which translates axial movement into radial movement of air seal segments to adjust clearance, supported by a full-hoop mount ring and actuated by a pneumatic or mechanical system to maintain optimal clearance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the radial tip clearance is designed for high power operations, then blade tips do not rub against BOAS, but radial tip clearance increases when engine power is reduced
Solution Approach 1:
The air seal segments are made movable rather than fixed, allowing them to dynamically adjust their radial position in response to changing engine operating conditions. This dynamic adjustment capability enables the system to maintain optimal blade tip clearance across varying power levels, resolving the contradiction between reliability and productivity.
Solution Approach 2:
The system incorporates sensors that monitor blade tip clearance and provide feedback to the control system. Based on this feedback, the control system actuates the air seal segments to maintain optimal clearance, creating a closed-loop control system that adapts to changing operating conditions and resolves the clearance inconsistency problem.
2Manufacturing precision
If multiple air seal segments are used to control clearance, then clearance control precision improves, but device complexity increases
Solution Approach 1:
The air seal assembly is divided into multiple independent air seal segments that can move radially independently. This segmentation allows for precise local adjustment of clearance at different angular positions, improving overall clearance control precision while keeping each individual segment relatively simple in structure.
Solution Approach 2:
Multiple air seal segments are combined with a common actuation mechanism and control system. This merging approach allows the system to achieve precise clearance control through coordinated movement of multiple segments while reducing overall device complexity by sharing common components and control logic.
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 system effectively maintains consistent radial tip clearance across varying operational conditions, enhancing engine performance and reducing the risk of blade-shroud contact, with a simplified design that minimizes moving parts and complexity.
Implementation Method 1
An active blade tip clearance control system utilizes an annular piston with lift lugs and blade outer air seal segments, which translates axial movement into radial movement of air seal segments to adjust clearance
Data Source
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AI summary
An active clearance control system for a gas turbine engine includes an annular piston with a multiple of piston lift lugs. A method of active blade tip clearance control for a gas turbine engine includes translating axial movement of an annular piston to radial movement of a multiple of blade outer air seal segments.