Variable Stator Vane with Locally Swept Leading Edge
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Solution Overview
Problem
Conventional variable stator vanes in aircraft gas turbine engines experience significant endwall leakage due to pressure gradients, leading to aerodynamic losses and mechanical instability, with attempts to reduce leakage either increasing trailing edge gaps or compromising mechanical robustness.
Innovation Solution
The design incorporates a locally swept leading edge for variable stator vanes, where the leading edge is coextensive with the button forward edge portion, minimizing endwall gaps and maintaining optimal mechanical positioning to reduce leakage and enhance robustness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional variable stator vanes with aft swept leading edge at root and forward swept leading edge at tip are used, then mechanical robustness and trailing edge support are improved, but leading edge endwall gaps increase causing significant endwall leakage and aerodynamic losses
Solution Approach 1:
The patent applies local quality by implementing different leading edge sweep configurations at different locations: the root leading edge is swept aft while the tip leading edge is swept forward. This localized differentiation allows the root region to maintain mechanical robustness and trailing edge support, while the tip region reduces endwall gaps and minimizes endwall leakage, thereby resolving the contradiction between mechanical strength and energy loss
Solution Approach 2:
The patent segments the leading edge into distinct root and tip regions with different sweep characteristics. The root leading edge maintains aft sweep for structural support, while the tip leading edge features forward sweep to reduce endwall gaps. This segmentation allows each region to be optimized independently for its specific functional requirements, balancing mechanical robustness with aerodynamic efficiency
2Reliability
If rotational axis and buttons are positioned to balance leading edge and trailing edge gaps, then mechanical performance is improved, but endwall leakage still occurs reducing compressor efficiency
Solution Approach 1:
The patent applies local quality by implementing different leading edge sweep configurations at different locations: the root leading edge is swept aft while the tip leading edge is swept forward. This localized differentiation allows the root region to maintain mechanical robustness and trailing edge support, while the tip region reduces endwall gaps and minimizes endwall leakage, thereby resolving the contradiction between mechanical strength and energy loss
Solution Approach 2:
The patent segments the leading edge into distinct root and tip regions with different sweep characteristics. The root leading edge maintains aft sweep for structural support, while the tip leading edge features forward sweep to reduce endwall gaps. This segmentation allows each region to be optimized independently for its specific functional requirements, balancing mechanical robustness with aerodynamic efficiency
Data Source
AI summary
Variable stator vane assemblies and stator vanes thereof having a local swept leading edge are provided. The variable stator vane comprises an airfoil disposed between spaced apart inner and outer buttons centered about a rotational axis. The inner and outer buttons each have a button forward edge portion. The airfoil includes leading and trailing edges, pressure and suction sides, and a root and a tip. The leading edge, at least a portion of which extends forward of the buttons, includes a local forward sweep at the root, thereby forming a locally swept root of the leading edge thereat. The button forward edge portion of the inner button is substantially vertically aligned with the locally swept leading edge root. Methods are also provided for minimizing endwall leakage in the variable stator vane assembly using the same.