Turbine Engine Seal Support Assembly for Dynamic Radial Clearance
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Solution Overview
Problem
Existing seal support systems in gas turbine engines fail to effectively manage radial gaps between rotor shafts and stator vanes, leading to leakage and wear during low delta pressure conditions and transient events, such as start-up, stall, or sudden pressure surges.
Innovation Solution
A seal member support system utilizing a tangential spring-based retraction mechanism that holds seal members radially away from the rotor shaft during low delta pressure conditions, allowing them to move inward as pressure increases to form a seal and return outward when pressure decreases, reducing rotor scrub and wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If seal members are held radially away from the rotor shaft during low delta pressure conditions, then wear and damage are minimized, but leakage occurs during operation
Solution Approach 1:
The seal support assembly uses a spring mechanism to dynamically adjust the radial position of seal members based on operating conditions. During low delta pressure conditions, the spring holds seal members radially outward to prevent wear. During high delta pressure conditions, the pressure differential overcomes the spring force, allowing seal members to move radially inward to contact the rotor shaft and prevent leakage. This dynamic adjustment resolves the contradiction between minimizing wear and maintaining seal effectiveness.
Solution Approach 2:
The system changes the radial position parameter of seal members in response to pressure condition changes. The spring-based mechanism allows the seal members to automatically adjust their position between two states: retracted (radially outward) during low pressure differential conditions and extended (radially inward) during high pressure differential conditions. This parameter change enables the system to optimize performance for different operating scenarios.
2Reliability
If seal members contact the rotor shaft continuously to prevent leakage, then seal effectiveness is improved, but rotor scrub and wear increase
Solution Approach 1:
Instead of continuous contact, the seal members dynamically adjust their contact with the rotor shaft based on pressure differential. The spring mechanism allows seal members to remain non-contacting during normal operation, eliminating continuous rotor scrub. When leakage prevention is needed, the pressure differential drives the seal members into contact temporarily. This dynamic approach maintains seal effectiveness while minimizing wear.
Solution Approach 2:
The spring mechanism applies a preliminary outward radial force on the seal members to prevent them from contacting the rotor shaft during low pressure conditions. This preliminary anti-action (outward force) counteracts the inward pressure force, keeping seal members retracted and preventing unnecessary rotor scrub. Only when the pressure differential exceeds the spring force does contact occur, minimizing overall wear.
3Strength
If a spring-based retraction mechanism is used to hold seal members radially away, then wear is reduced, but device complexity increases
Solution Approach 1:
The spring-based retraction mechanism is a self-regulating system that automatically adjusts seal member position based on pressure differential without external control. The spring provides continuous outward force, and the pressure differential automatically overcomes this force when needed, causing seal members to move inward. This self-service mechanism reduces wear while maintaining relatively simple construction compared to actively controlled systems.
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 maintains a positive radial clearance between seal members and the rotor shaft, minimizing wear and damage by controlling seal movement in response to pressure changes, thereby enhancing the durability and efficiency of the turbine engine.
Implementation Method 1
a spring arrangement (114) extending between the carrier (104) and a first seal segment (110A) to counter a pressure on an outer pressurization surface (140)
Data Source
AI summary
A turbine engine is provided. The gas turbine engine defines a radial direction, and includes: a rotor; a stator comprising a carrier; a seal assembly disposed between the rotor and the stator, the seal assembly comprising a seal segment having a seal face forming a fluid bearing with the rotor; and a seal support assembly comprising a torsional spring extension extending from the carrier, from the seal segment, or both, to bias the seal segment along the radial direction.