Active Centering Control for Annular Turbine Flowpath Structures
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Solution Overview
Problem
In gas turbine engines, the small clearances between rotor blades and the ring-shroud are prone to thermal expansion and relative movement, leading to undesirable wear or damage due to contact between the blades and the inner surface of the ring-shroud.
Innovation Solution
A clearance control apparatus that monitors the position of the rotor and ring-shroud using sensors and adjusts the ring-shroud's position relative to the casing through an actuation system to maintain a minimum tip clearance, ensuring the rotor and ring-shroud remain concentric and preventing damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If small clearances are used between rotor blades and ring-shroud, then engine efficiency is improved, but thermal expansion and relative movement cause contact between blades and ring-shroud leading to wear and damage
Solution Approach 1:
The ring-shroud is made movable relative to the rotor assembly through an actuation system, allowing dynamic adjustment of the clearance between blades and ring-shroud. This transforms the previously static clearance into a dynamic parameter that can be adjusted in real-time to prevent contact while maintaining efficiency.
Solution Approach 2:
A sensing system continuously monitors the relative position between the rotor and ring-shroud, providing feedback to the actuation system. This closed-loop control enables the system to detect and correct clearance variations caused by thermal expansion and relative movement, preventing blade-ring-shroud contact.
2Reliability
If the ring-shroud is made movable to maintain clearance, then blade-ring-shroud contact is prevented, but device complexity increases due to actuation and sensing systems
Solution Approach 1:
The actuation system serves multiple functions: it adjusts the ring-shroud position to maintain clearance, compensates for thermal expansion, and prevents blade-ring-shroud contact. This multi-functionality reduces the need for separate systems and minimizes overall device complexity.
Solution Approach 2:
The sensing system automatically detects clearance variations and triggers the actuation system to correct them, enabling the system to self-regulate the clearance without external intervention. This autonomous operation simplifies control and reduces operational complexity.
Data Source
AI summary
A rotor assembly apparatus that includes a rotatable component and a ring-shroud. The rotatable component is mounted for rotation about a first axis. The ring-shroud defines an inner surface that surrounds the rotatable component and that defines a second axis. A sensing system is configured to monitor the position of the first axis relative to the second axis. A casing surrounds the ring-shroud and an actuation system is configured to move the ring-shroud relative to the casing, in response to the sensing system.