Thermally Compensated Synchronization Ring for Variable Stator Vane
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Solution Overview
Problem
Variable vane accuracy in gas turbine engines is compromised by thermal differences between the synchronization ring and its mounting case, leading to positioning errors, and active thermal compensation solutions are often avoided due to weight concerns.
Innovation Solution
A variable vane assembly design that redirects gas from the main flow gaspath to the synchronization ring, using a bushing and vane arm to reduce temperature differences between the synchronization ring and the case, thereby minimizing the required design gap and improving accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If active thermal compensation solutions are used, then positioning accuracy of the synchronization ring is improved, but weight increases significantly
Solution Approach 1:
The system uses the existing main flow gaspath to provide thermal compensation automatically. The gas flow that is already present in the system is redirected through the vane arm to cool the synchronization ring, eliminating the need for separate active thermal compensation systems and their associated weight.
Solution Approach 2:
The vane arm serves as an intermediary component that performs dual functions: it mechanically transmits motion to rotate the stator vane and simultaneously acts as a flow path to redirect gas for thermal compensation of the synchronization ring.
2Temperature
If a larger design gap is provided between the synchronization ring and case, then thermal expansion clearance is improved, but positioning accuracy deteriorates
Solution Approach 1:
The system changes the temperature parameter of the synchronization ring by redirecting cooler gas from the main flow gaspath through the vane arm to cool the ring, thereby reducing thermal expansion and allowing for a smaller design gap while maintaining positioning accuracy.
3Temperature
If gas is redirected from the main flow gaspath to the synchronization ring, then thermal compensation is improved, but gas flow in the main gaspath is reduced
Solution Approach 1:
The vane arm is designed to perform multiple functions simultaneously: it acts as a mechanical linkage to rotate the stator vane and also serves as a flow path to redirect gas for thermal compensation. This multi-functionality allows thermal compensation without requiring separate dedicated flow paths that would significantly reduce main gaspath flow.
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
This design reduces temperature differences between the synchronization ring and the case, enhancing the accuracy of the variable vane positioning by allowing a smaller gap, thus improving the stall margin of the engine's fan and compressor sections.
Implementation Method 1
The gas redirected to the synchronization ring may reduce a temperature difference between the synchronization ring and the case
Data Source
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AI summary
A variable vane assembly including a variable stator vane (110) disposed in a main flow gaspath (114), the variable stator vane having a vane stem (111). The assembly also includes a case (118) located at a radially outward location of the variable stator vane, the vane stem extending through a port (116) of the case, the port defined by a port wall (120), a clearance (124) defined by the vane stem and a port wall to allow gas from the main flow gaspath to pass therethrough. The assembly further includes a synchronization ring (108) spaced from the case to define a gap (130). The assembly yet further includes a vane arm (102) operatively coupled to a synchronization ring and to the vane stem, the vane arm redirecting gas from the main flow gaspath to the synchronization ring.