Variable Vane Labyrinth Seal Reduces Leakage and Friction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing variable vane seal technologies in gas turbine engines suffer from leakage issues due to high pressure air escaping into lower pressure cavities, leading to decreased engine performance and increased frictional loads, particularly in compressor stages.
Innovation Solution
A variable vane assembly incorporating a labyrinth seal that creates a tortuous path for air leakage, utilizing a bushing and button structure with low-friction materials and knife projections, which reduces actuator loads and frictional losses without relying on compressive loads or air/spring pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional seal is used between the variable vane and casing, then sealing is provided, but high pressure air escapes into lower pressure cavities causing leakage
Solution Approach 1:
The seal is divided into multiple segments including a first seal segment and a second seal segment positioned at different locations along the variable vane. This segmentation allows each segment to independently address leakage at specific locations, improving overall sealing effectiveness while maintaining low friction
Solution Approach 2:
A spacer acts as an intermediary component between the variable vane and the casing, providing a structure that supports the seal segments and creates a labyrinthine path for fluid flow. The spacer enables the seal to function without direct contact between the variable vane and casing, reducing frictional loads
2Reliability
If a tight seal is used to prevent leakage, then sealing is improved, but frictional loads increase
Solution Approach 1:
The spacer serves as a mediator that allows the seal segments to contact the variable vane and casing surfaces without requiring high compressive loads. The labyrinthine path created by the spacer and seal segments prevents leakage while maintaining low frictional contact
Solution Approach 2:
The seal design changes the sealing mechanism from relying on high contact pressure to utilizing a labyrinthine path with minimal contact. The seal segments are positioned to create tortuous fluid paths rather than relying on tight compression, thereby reducing frictional loads while maintaining sealing effectiveness
3Reliability
If high compressive loads are applied to maintain seal position, then sealing is improved, but actuator loads increase
Solution Approach 1:
The seal segments and spacer configuration create a self-positioning mechanism where the components naturally maintain their sealing positions through the labyrinthine geometry rather than requiring high compressive loads. The design allows the seal to function effectively with minimal actuator force, as the labyrinthine path itself provides the sealing action
Solution Approach 2:
The invention changes the sealing parameter from compressive load-dependent to geometry-dependent. By designing the labyrinthine path with specific geometric features, the seal maintains effectiveness without requiring high compressive loads, thereby reducing actuator power requirements
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 labyrinth seal effectively minimizes fluid leakage and reduces actuator loads, enhancing engine performance by creating a low-friction sealing arrangement that maintains vane position without increasing frictional loads, thus improving overall engine efficiency.
Implementation Method 1
A labyrinth seal is positioned between the bushing and the button portion
Implementation Method 2
utilizing a bushing and button structure with low-friction materials
Data Source
AI summary
A variable vane assembly for a gas turbine engine is disclosed herein. The variable vane assembly includes a vane operable to pivot about a pivot axis. The vane includes a flap portion positionable in a fluid stream for controlling a flow of fluid. The vane also includes a stem portion for mounting the flap portion. The vane also includes a button portion positioned between the flap portion and the stem portion along the pivot axis. The button portion is wider than the stem portion in at least one plane containing the pivot axis. The variable vane assembly also includes a bushing encircling the stem portion and abutting the button portion. The variable vane assembly also includes a labyrinth seal positioned between the bushing and the button portion.