Stator Vane Stage Retention for Thermal Growth and Sealing
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Solution Overview
Problem
Turbine stator vanes experience significant thermal stresses due to constrained thermal expansion, limiting their ability to accommodate growth and leading to potential structural failure.
Innovation Solution
A gas turbine engine design featuring an annular stator vane stage with an inner and outer radial shroud, a retaining ring, and a flange that allows for radial movement, along with lugs and seals to accommodate thermal growth and mitigate stress, while maintaining a seal to prevent cooling air leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the stator vanes are constrained by the inner and outer shrouds, then the structural stability is improved, but the thermal stress increases due to restricted thermal expansion
Solution Approach 1:
The stator vane assembly is segmented into multiple components (inner shroud, outer shroud, stator vanes, retaining ring) that can move independently relative to each other. The stator vanes are retained by the retaining ring rather than being rigidly constrained by the shrouds, allowing the vanes to expand radially while the shrouds remain relatively stable.
Solution Approach 2:
The retaining ring is designed to allow radial movement of the stator vanes relative to the ring itself. This dynamic retention mechanism enables the stator vanes to accommodate thermal expansion while maintaining their positional stability in the axial direction, thereby reducing thermal stress.
2Stress or pressure
If the stator vanes are allowed to expand freely, then the thermal stress is reduced, but the positional stability deteriorates
Solution Approach 1:
The retention system is segmented into the retaining ring and the stator vanes as separate movable components. This segmentation allows the vanes to expand radially while the retaining ring maintains the axial position, achieving both stress reduction and positional stability.
Solution Approach 2:
The retaining ring provides different degrees of constraint in different directions: it maintains axial positional stability while allowing radial thermal expansion. This anisotropic constraint approach addresses both requirements simultaneously.
3Strength
If the flange is rigidly secured to the retaining ring, then the structural integrity is improved, but the thermal growth accommodation capability is reduced
Solution Approach 1:
The flange is designed with a dynamic retention mechanism that allows it to move radially relative to the retaining ring. This enables the flange to accommodate thermal growth while maintaining structural integrity through the retained connection to the outer shroud.
Solution Approach 2:
The retention mechanism allows the flange to change its radial position parameter in response to thermal expansion, while maintaining its connection to the outer shroud. This parameter change capability enables thermal growth accommodation without compromising structural integrity.
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 design enhances thermal growth accommodation, reduces stress concentrations, and prevents cooling air leakage, thereby improving the durability and efficiency of the stator vane stage.
Implementation Method 1
The high-temperature stator vanes are restricted in their ability to expand or grow due to the surrounding cooler inner and outer shrouds
Implementation Method 2
the forward seal surface and the aft seal surface each may have a surface configuration that facilitates a sliding contact therebetween
Data Source
AI summary
A gas turbine engine is provided that includes a compressor section, a combustion section, and a turbine section. The turbine section has a rotor stage disposed adjacent an annular stator vane stage. The annular stator vane stage includes an annular inner and outer radial shrouds, stator vanes, and a retaining ring. The stator vanes are circumferentially spaced apart from one another, extending between the shrouds. The inner radial shroud is mechanically engaged with a first engine support structure at a first position axially forward of the plurality of stator vanes, and the outer radial shroud is mechanically engaged with a second engine support structure at a second position axially forward of the plurality of stator vanes. The annular stator vane stage includes a flange extending outward from the outer radial shroud that is contiguous with the retaining ring.