Turbine Engine Seal Support Assembly for Adaptive Radial Clearance
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Solution Overview
Problem
Existing seal systems in gas turbine engines face challenges in maintaining a positive radial clearance between seal members and the rotor shaft under varying operating conditions, leading to wear and potential rubs during low delta pressure conditions and transients.
Innovation Solution
A seal support assembly that includes a spring arrangement and a seal assembly with angled seal segments, allowing for radial movement and adjustment to maintain tight clearances with the rotor, using shape memory alloys for adaptive stiffness control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a fixed seal system is used to maintain clearance, then manufacturing precision is improved, but reliability deteriorates due to wear and rubs during low delta pressure conditions and transients
Solution Approach 1:
The seal support assembly incorporates a spring arrangement that enables dynamic adjustment of the seal assembly's radial position. The spring constant is specifically selected to allow the seal assembly to move radially in response to varying pressure differentials and rotor vibrations, transitioning from a fixed clearance system to a dynamic adaptive system that maintains reliable sealing under all operating conditions.
Solution Approach 2:
The system changes the physical state and position of the seal assembly by utilizing pressure differential-driven movement. During low delta pressure conditions and transients, the spring arrangement allows the seal assembly to shift radially, changing its clearance parameter adaptively rather than maintaining a fixed manufactured clearance, thereby preventing wear and rubs.
2Reliability
If a spring arrangement is added to allow radial movement, then reliability is improved, but device complexity increases
Solution Approach 1:
The spring arrangement is designed to be passively actuated by the existing pressure differential across the seal assembly. The system uses the engine's own operating conditions (pressure differences and vibrations) to automatically adjust the seal position without requiring external control systems, actuators, or complex mechanisms, thereby improving reliability while minimizing added complexity.
Solution Approach 2:
The spring constant is specifically selected to provide the optimal balance between maintaining tight clearances during normal operation and allowing sufficient radial movement during transients and low delta pressure conditions. This parameter optimization ensures reliable sealing performance without requiring overly complex adjustment mechanisms.
3Productivity
If tight clearances are maintained during high pressure conditions, then productivity is improved, but object-affected harmful factors increase due to rotor vibrations
Solution Approach 1:
The spring arrangement creates a dynamic clearance system that adapts to rotor vibrations. During high pressure conditions, the spring maintains tight clearances for efficient sealing, but during vibrations and transients, it allows the seal assembly to move radially, accommodating the harmful vibrations and preventing contact and wear between the seal and rotor.
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 accommodates rotor vibrations and pressure changes, reducing wear and airflow leakage while minimizing rubs and maintaining efficient sealing performance across different operating conditions.
Implementation Method 1
A seal support assembly that includes a spring arrangement and a seal assembly with angled seal segments, allowing for radial movement and adjustment to maintain tight clearances with the rotor
Implementation Method 2
using shape memory alloys for adaptive stiffness control
Implementation Method 3
the seal assembly with angled seal segments, allowing for radial movement and adjustment to maintain tight clearances with the rotor
Data Source
AI summary
A turbine engine is provided. The turbine engine includes: a rotor; a stator having a carrier; a seal support assembly coupled to the carrier; and a seal assembly disposed between the rotor and the stator and supported by the seal support assembly, the seal assembly defining a high pressure side and a low pressure side and including a plurality of seal segments, the plurality of seal segments having a first seal segment, the first seal segment having a seal face configured to form a fluid bearing with the rotor, a lip assembly, and a body, the lip assembly positioned on the high pressure side, the lip assembly including a seal lip having a high pressure surface defining a first angle with an axial direction and a low pressure surface defining a second angle with the axial direction, the second angle being greater than the first angle.