Full Hoop Thermal Control Ring for Gas Turbine Blade Tip Clearance
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Solution Overview
Problem
Gas turbine engines face performance and efficiency issues due to varying radial tip clearance caused by thermal expansion and centrifugal loading, leading to increased core air leakage and potential blade tip rub conditions, which are not adequately addressed by existing blade tip clearance control systems.
Innovation Solution
A blade tip clearance control system featuring a full hoop blade outer air seal carrier ring with an integrated full hoop thermal control ring forming an interference fit, utilizing materials with different coefficients of thermal expansion to passively control radial tip clearance through thermal expansion management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If segmented BOAS carriers are used to control blade tip clearance, then fuel consumption performance is improved, but stability is reduced at the segmented carrier intersurfaces
Solution Approach 1:
The BOAS carrier is divided into multiple segments that can independently expand and contract radially. Each segment is supported by independent springs, allowing localized adjustment while maintaining overall stability. The segmented design enables the carrier to adapt to thermal expansion variations without compromising structural integrity at the intersurfaces.
Solution Approach 2:
The BOAS carrier incorporates dynamic elements including springs and dampers that allow the segments to move radially in response to thermal and mechanical conditions. This dynamic capability enables the system to maintain stability during operation while achieving the clearance control benefits needed for improved fuel consumption.
2Loss of energy
If radial tip clearance is reduced to improve engine performance, then leakage is reduced, but blade tip rub conditions may occur under thermal expansion
Solution Approach 1:
The system changes the radial clearance parameter dynamically in response to operating conditions. The BOAS carrier segments can radially position themselves to maintain optimal clearance, reducing air leakage during normal operation while automatically increasing clearance when thermal expansion conditions approach rub limits.
Solution Approach 2:
The clearance control system incorporates feedback mechanisms where the position and thermal state of the blades and BOAS carrier are continuously monitored. This feedback allows the system to adjust the carrier position to maintain safe clearance margins while minimizing leakage, preventing blade tip rubs under varying thermal expansion conditions.
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 a consistent radial tip clearance, reducing air leakage and preventing blade tip rubs, thereby enhancing engine performance, efficiency, and component life by leveraging thermal expansion differences between materials.
Implementation Method 1
utilizing materials with different coefficients of thermal expansion to passively control radial tip clearance through thermal expansion management
Data Source
AI summary
A clearance control system for a gas turbine engine includes a full hoop blade outer air seal carrier ring, a full hoop thermal control ring at least partially contained within the full hoop blade outer air seal blade outer air seal carrier ring to form an interference fit therebetween, and a multiple of blade outer air seals mounted to the full hoop blade outer air seal carrier ring.