Clamped Vane Arc Segment Load Transmission
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Solution Overview
Problem
Gas turbine engines face challenges in efficiently managing radial, tangential, and axial load transmissions within the vane assemblies, particularly in high-temperature environments, where existing designs may not effectively distribute and bear these loads without inducing thermal distortion or increasing tensile bending stresses.
Innovation Solution
The vane arc segment design includes radially inner and outer platforms with an airfoil mechanically clamped between them, featuring protrusions with faces oriented normal to radial, tangential, and axial load transmission directions, and ribs within the airfoil to transmit and distribute loads effectively, while minimizing surface area for thermal insulation and reducing stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing vane designs are used in high-temperature environments, then the vane assembly can operate under aerodynamic loads, but thermal distortion increases and load transmission efficiency decreases
Solution Approach 1:
The vane assembly is divided into multiple modular vane arc segments that can be arranged in an annular configuration. Each segment includes separate load-transmitting features (protrusions) and airfoil sections, allowing independent optimization of thermal management and load bearing. The segmentation enables better heat dissipation pathways while maintaining structural integrity under thermal distortion.
Solution Approach 2:
The vane arc segments feature localized protrusions with faces oriented normal to specific load transmission directions (radial, tangential, axial). This local quality optimization ensures that load-bearing surfaces are precisely positioned to handle aerodynamic loads while minimizing thermal exposure areas. The airfoil sections have tailored thermal barrier coatings or material properties in specific zones to resist thermal distortion where most critical.
2Strength
If traditional clamping structures are used, then the airfoil can be secured between platforms, but tensile bending stresses increase under aerodynamic loads
Solution Approach 1:
The tie rod or spar is pre-tensioned to apply clamping force to the airfoil before aerodynamic loads are applied. This preliminary action creates a compressive pre-stress state in the airfoil that counteracts the tensile bending stresses that would otherwise develop under aerodynamic loading, thereby reducing overall stress levels and preventing failure.
Solution Approach 2:
The tie rod or spar acts as an intermediary mechanical element between the radially inner and outer platforms. It transmits and distributes clamping forces uniformly across the airfoil section, preventing stress concentration at critical points. The intermediary structure allows for optimized force distribution that reduces tensile bending stresses while maintaining secure clamping.
3Force
If larger surface area is provided for load transmission, then load bearing capacity increases, but thermal insulation effectiveness decreases
Solution Approach 1:
The protrusions have faces oriented normal to specific load transmission directions, concentrating load-bearing surface area only where mechanically necessary. The airfoil sections have minimized surface area in regions exposed to high thermal environments while maintaining adequate load transmission capability. This local optimization allows sufficient load bearing capacity with reduced thermal exposure area.
Solution Approach 2:
The vane arc segments are arranged in an annular configuration around the engine core, utilizing the circumferential dimension to distribute load transmission paths. This three-dimensional arrangement allows load forces to be transmitted through multiple paths and directions, reducing the need for large single-surface contact areas and thereby minimizing thermal exposure while maintaining load bearing capacity.
Data Source
Figure 1~3
Figure 4A~4B
Figure 5A~5B
AI summary
A vane arc segment (62) includes a radially inner and outer platforms (64,66) and an airfoil (72) mechanically clamped between the platforms (62,64). The airfoil (72) has an airfoil section that extends radially between radially inner and outer fairing platforms (74,76). At least one of the fairing platforms (74,76) includes forward and aft sides (82a,82b), circumferential sides (84a,84b), and a gas path side (86a) and an opposed radial side (86b). The radial side (86b) includes a plurality of protrusions (88) that have faces that are oriented substantially normal to, respectively, radial, tangential, and axial load transmission directions of the airfoil such that the faces, respectively, primarily bear radial, tangential, and axial load transmissions of the airfoil.