Segmented Annular Seal Leakage Reduction
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Solution Overview
Problem
Current gas turbine engine seal systems face challenges in effectively reducing gas flow leakage around turbine blades due to the radial gap between the blades and the shroud, which affects engine efficiency and performance.
Innovation Solution
A segmented annular seal system is introduced, comprising carriage arc segments and seal arc segments with a ramped interface and spring members, allowing for radial support and circumferential movement of the seal arc segments, and featuring tortuous passages to minimize leakage through labyrinth seals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a segmented annular seal system is used to reduce gas flow leakage, then sealing effectiveness is improved, but device complexity increases
Solution Approach 1:
The seal system is divided into multiple discrete seal arc segments arranged circumferentially, each independently mounted on carriage arc segments. This segmentation allows the seal to conform to the annular space while maintaining manageable complexity through modular construction, directly reducing gas flow leakage through the segmented sealing surfaces.
Solution Approach 2:
The seal arc segments are designed with circumferential movement capability along the ramped interfaces of the carriage arc segments, allowing the seal system to dynamically adapt to thermal expansion, manufacturing tolerances, and operational conditions. This dynamic adjustment optimizes sealing effectiveness without requiring an overly complex fixed structure.
2Reliability
If spring members are used to bias seal arc segments radially outward, then sealing contact is improved, but stress on sensitive materials increases
Solution Approach 1:
The spring members provide controlled radial biasing force that can be adjusted through spring selection and positioning, optimizing the contact pressure between seal arc segments and the annular space. This parameter adjustment ensures reliable sealing contact while maintaining stress levels within acceptable limits for sensitive blade tip materials.
3Loss of energy
If circumferential offset between seal joints and carriage joints is introduced, then tortuous passages are formed to reduce leakage, but manufacturing precision requirements increase
Solution Approach 1:
The circumferential offset between seal joints and carriage joints creates tortuous leakage passages that increase flow resistance and reduce gas flow leakage. The segmented modular design allows this offset to be incorporated through standard joint configurations, managing manufacturing precision requirements through repeatable assembly procedures.
Solution Approach 2:
The circumferential offset and tortuous passage geometry create a curved, labyrinthine flow path that increases the effective sealing length without requiring excessive radial clearance. This curved path configuration enhances leakage reduction while maintaining reasonable manufacturing tolerances for the joint interfaces.
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 segmented annular seal system significantly reduces gas flow leakage by providing a compliant, low-stress mounting for sensitive materials and maintaining a centered position of the seal arc segments, enhancing the overall efficiency and performance of the gas turbine engine.
Implementation Method 1
each of the carriage arc segments includes a respective second spring member radially biasing both of the two of the seal arc segments
Implementation Method 2
the support member supports each of the two of the seal arc segments in a respective ramped interface such that each of the two of the seal arc segments is circumferentially moveable
Implementation Method 3
The circumferential offset between the circumferential seal joints and the circumferential carriage joints define tortuous passages between a radially inner side of the segmented annular seal and a radially outer side of the segmented annular seal support
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
A seal system includes a segmented annular seal support (66) that has carriage arc segments (70) arranged circumferentially in circumferential carriage joints (72), and a segmented annular seal (68) that includes seal arc segments (74) arranged end-to-end in circumferential seal joints (76). The circumferential seal joints (76) are circumferentially offset from the circumferential carriage joints (72).