Axially Sloped Vane Flange for Gas Turbine Stress Reduction
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Solution Overview
Problem
Traditional support schemes for ceramic matrix composite and stress-limited metallic alloy vane segments in gas turbine engines face challenges due to high stress concentrations, complex geometries, and manufacturing difficulties, which can lead to exceeding material limits under aerodynamic and thermal loads.
Innovation Solution
A vane arc segment design featuring a continuous airfoil piece with axially-sloped circumferential mate faces and a flange that projects from the non-gaspath side, oriented orthogonally to the total aerodynamic load vector, facilitates low-stress mounting and efficient load transmission using a ceramic matrix composite material with continuous fiber plies, minimizing pressure-driven stresses and thermal gradients.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional support schemes are used for ceramic matrix composite vane segments, then the structure can be assembled, but high stress concentrations occur leading to exceeding material limits
Solution Approach 1:
The vane segment is divided into distinct functional zones: a mounting portion with axially-sloped circumferential mate faces for stress-distributed attachment, and a gas path portion for aerodynamic function. This segmentation allows the mounting portion to be optimized for stress distribution while the gas path portion maintains aerodynamic performance.
Solution Approach 2:
The mounting portion features axially-sloped circumferential mate faces with specific geometry to distribute stresses, while the gas path portion has different geometric characteristics optimized for airflow. This local differentiation ensures that stress concentration is minimized at the mounting interface while maintaining gas path functionality.
2Ease of manufacture
If complex geometries are used in traditional support schemes, then mounting capability is achieved, but manufacturing difficulties increase
Solution Approach 1:
Instead of using complex curved mounting surfaces that are difficult to manufacture, the invention inverts the approach by using axially-sloped planar faces. These sloped flat surfaces are much easier to manufacture while achieving the same functional goal of stress-distributed mounting.
Solution Approach 2:
The invention replaces complex curved geometries with simplified axial slopes. The axially-sloped circumferential mate faces use simple planar surfaces inclined at specific angles rather than complex curved surfaces, significantly reducing manufacturing complexity while maintaining structural functionality.
3Force
If traditional mounting geometries are used, then attachment is achieved, but aerodynamic performance is compromised due to pressure-driven stresses
Solution Approach 1:
The mounting portion features asymmetric axially-sloped circumferential mate faces that are specifically oriented to be substantially orthogonal to the total aerodynamic load vector. This asymmetric geometry allows efficient transmission of aerodynamic forces while minimizing pressure-driven stresses that would cause failure.
Data Source
Figure 1~2A
Figure 2B
Figure 3A~3B
AI summary
A vane arc segment (60) includes a continuous airfoil piece (62) that defines first and second platforms (63, 64) and an airfoil section (66) that extends between the first and second platforms (63, 64). The airfoil section (66) has a pressure side and a suction side (66c, 66d). The first platform (63) defines axially-sloped suction and pressure side circumferential mate faces (63a/63b), first and second axial sides (63c, 63d), a gaspath side (63e), a non-gaspath side (63f), and a flange (68) that projects from the non-gaspath side (63f). The flange (68) extends along at least a portion the axially-sloped suction side circumferential mate face (63a).