Variable-Pitch Turbine Stator Sector for Passage Section Homogeneity
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Solution Overview
Problem
Turbine stators in aircraft turbomachines suffer from misalignment between sectors, leading to non-homogeneous passage sections and efficiency losses, which are difficult to correct post-manufacture and cannot be adjusted during the engine's life.
Innovation Solution
Implementing variable pitch blades with an axis of rotation downstream of the head and root, allowing for adjustable pitch adjustments to homogenize the passage section and optimize efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If machining operations are performed to correct misalignment, then passage section homogeneity is improved, but manufacturing time and complexity increase
Solution Approach 1:
The patent applies preliminary action by incorporating alignment features (such as tapered surfaces, locating pins, or keyed interfaces) directly into the sector and ring components during manufacturing. This allows the sectors to be pre-aligned and fixed in their correct positions before final assembly, eliminating the need for post-assembly machining operations to correct misalignment.
Solution Approach 2:
The patent introduces intermediary alignment elements (such as adjustable shims, positioning blocks, or modular interface components) between the sectors and rings that facilitate precise alignment during assembly. These intermediaries act as mediators that enable accurate passage section homogeneity without requiring complex machining operations on the main components.
2Adaptability or versatility
If the turbine stator is manufactured with fixed geometry, then manufacturing is simpler, but the passage section cannot be adjusted during engine life
Solution Approach 1:
The patent applies dynamics by making the stator geometry adjustable rather than fixed. Sectors are designed with movable or reconfigurable features that allow the passage section to be modified during engine operation or maintenance. This enables the stator to adapt to different operating conditions while maintaining a relatively simple base structure.
Solution Approach 2:
The patent applies segmentation by dividing the stator into modular sectors that can be independently adjusted, repositioned, or replaced. This modular approach allows for passage section adjustment without requiring complex integrated mechanisms, as each sector can be individually configured to achieve the desired overall geometry.
3Ease of manufacture
If sectors are assembled around the axis, then the turbine stator can be manufactured, but misalignment between sectors occurs
Solution Approach 1:
The patent applies asymmetry by incorporating asymmetric alignment features (such as tapered interfaces, non-circular locating elements, or directionally keyed surfaces) between sectors and rings. These asymmetric features ensure that sectors can only be assembled in their correct rotational positions, preventing misalignment while maintaining ease of assembly through the self-aligning nature of the asymmetric interfaces.
Data Source
AI summary
A sector of a turbine stator for a turbine of an aircraft turbomachine, the sector having an outer platform and an inner platform which are coaxial along an axis. The sector further includes at least one blade which connects the outer and inner platforms together, with the blade being variable-pitch about an axis of rotation of the blade. The blade can include an aerodynamic body delimited radially by a head and a root, the head being placed with a first functional clearance in an opening of the outer platform, the root being placed with a second functional clearance in a cavity of the inner platform, the axis of rotation of the blade being located downstream of the head and the root.