Turbomachine Platform Trailing Edge Seal Design
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Solution Overview
Problem
Traditional turbomachine seals fail to effectively prevent gaspath ingestion into the blade-vane cavity through the mateface gap between platform trailing edges, leading to reduced durability and increased fuel consumption due to insufficient cooling flow.
Innovation Solution
An annular or segmented platform trailing edge seal is designed to extend into the aft portion of the mateface gap between adjacent blade platforms, matching the shape of the platform trailing edge to minimize flow entry into the blade-vane cavity, and can be either integrally formed or attached to the blade platform using friction, thermal, or expansion fits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a traditional cooling flow is provided through the blade-vane gap, then cooling is provided to the blade-vane cavity, but hot flow still travels through the mateface gap between blades causing gaspath ingestion
Solution Approach 1:
The seal is divided into multiple segments that can be independently positioned and secured to the blade platform, allowing each segment to address specific portions of the mateface gap while maintaining overall sealing effectiveness across the blade interface
Solution Approach 2:
A seal element is introduced as an intermediary component between the adjacent blade platforms, extending into the mateface gap to physically block hot flow paths while allowing the cooling flow through the blade-vane gap to remain effective
2Reliability
If conventional sealing methods are used to prevent gaspath ingestion, then flow sealing is achieved, but the methods are costly in terms of flow loss impacting fuel consumption and turbine efficiency
Solution Approach 1:
The seal is designed with local quality variations including protrusions and retaining features positioned at specific locations on the blade platform to optimize sealing effectiveness at critical flow paths while minimizing overall flow restriction and energy loss
Solution Approach 2:
The seal geometry parameters including the extent of extension into the mateface gap, the shape and size of protrusions, and the material properties are optimized to achieve effective gaspath sealing while minimizing flow loss and energy consumption
3Reliability
If a seal extends into the mateface gap to prevent hot flow, then gaspath ingestion is reduced, but the seal must be securely attached to the blade platform requiring retention features
Solution Approach 1:
The seal integration features including protrusions and retaining structures are merged with the blade platform geometry, allowing the seal to be securely attached through friction fit, thermal fit, or expansion fit without requiring separate complex retention mechanisms
Solution Approach 2:
The seal utilizes the blade platform's own geometric features and material properties to achieve secure attachment through friction, thermal, or expansion fits, eliminating the need for additional external retention devices while maintaining reliable sealing
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 seal effectively prevents hot gas ingestion, reducing component temperatures and extending component lifespan while improving thrust specific fuel consumption by separating gaspath pressures, thus enhancing turbomachine efficiency.
Implementation Method 1
separating gaspath pressures
Implementation Method 2
reducing component temperatures
Data Source
Figure 1
Figure 2A~2B
Figure 2C~3
AI summary
A platform trailing edge seal for a turbomachine airfoil (e.g., a blade or vane) assembly includes a body configured to extend into an aft portion of a mateface gap defined between a circumferentially adjacent pair of turbomachine airfoil platforms to minimize flow from entering a blade-vane cavity through the aft portion of the mateface gap.