Variable Guide Vane Sealing for Gas Turbine Leakage
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Solution Overview
Problem
Variable stator vanes in gas turbine engines experience airflow leakage around their radially inner and outer ends due to lack of fixed attachment to bands, affecting engine performance, efficiency, and durability.
Innovation Solution
A variable guide vane assembly with a sealing element that forms a seal between the airfoil and the airfoil band, positioned within a cavity of the airfoil band, and an actuation member to rotate the airfoil, reducing leakage by pressurizing the cavity to enhance sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If variable stator vanes are made movable to vary airflow direction, then engine performance and efficiency are improved, but airflow leakage around radially inner and outer ends increases
Solution Approach 1:
A sealing element is positioned between the variable stator vane and the airfoil band to prevent airflow leakage. The sealing element acts as a flexible barrier that maintains the seal while allowing the vane to rotate about its axis to vary airflow direction.
Solution Approach 2:
The sealing element serves as an intermediary component between the movable variable stator vane and the stationary airfoil band. This intermediary allows the vane to move for performance optimization while preventing the harmful effect of airflow leakage around the radially inner and outer ends.
2Productivity
If variable stator vanes are made movable to vary airflow direction, then engine efficiency is improved, but sealing between airfoil and band becomes more difficult
Solution Approach 1:
The sealing element is positioned within a cavity of the airfoil band, creating a simplified sealing structure that accommodates the movable vane while maintaining the seal. This flexible sealing approach reduces the complexity compared to rigid sealing mechanisms.
3Adaptability or versatility
If variable stator vanes are made movable to vary airflow direction, then airflow control is improved, but leakage around radially ends increases
Solution Approach 1:
The sealing element maintains a seal between the movable variable stator vane and the airfoil band, preventing airflow leakage while allowing the vane to rotate and adapt airflow direction for optimized engine performance.
Solution Approach 2:
The sealing element acts as an intermediary that enables the variable stator vane to provide adaptable airflow control while simultaneously preventing the loss of airflow through leakage around the radially inner and outer ends.
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 minimizes airflow leakage, enhancing the performance and efficiency of gas turbine engines by ensuring a secure seal between the airfoil and the airfoil band, thereby improving durability and reducing operational losses.
Implementation Method 1
a sealing element operable to form a seal between the first end of the airfoil and the airfoil band
Implementation Method 2
The airfoil band defines an airflow passage for supplying pressurized air to the cavity to pressurize the cavity
Data Source
AI summary
A variable guide vane assembly is provided for a turbine defining a core air flowpath. The variable guide vane assembly includes an airfoil band defining a flowpath surface and a cavity. The variable guide vane assembly further includes an airfoil including a first end extending at least partially into the cavity of the airfoil band and an opposite second end, the airfoil extending generally along an axis between the first end and the second end and being moveable generally about the axis relative to the airfoil band. The variable guide vane assembly further includes a sealing element operable to form a seal between the first end of the airfoil and the airfoil band.