Turbomachine Fan Guide Vane Thermal Expansion Bending Compensation
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Solution Overview
Problem
The existing turbomachine fan stator vanes are subjected to significant bending stresses due to the helical component of the air flow, leading to deformation, misalignment of components, increased wear on bearings and gears, and potential blocking of thrust reversers.
Innovation Solution
The vanes are designed with a hollow structure featuring a central main duct for heat transfer fluid circulation and lateral ducts between the main duct and the leading/trailing edges, allowing differential thermal expansion to counteract aerodynamic bending forces, reducing the rotation of the outer casing relative to the inner casing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the vanes are designed with a hollow structure featuring a central main duct for heat transfer fluid circulation and lateral ducts between the main duct and the leading/trailing edges, allowing differential thermal expansion to counteract aerodynamic bending forces, then the bending deformation caused by aerodynamic forces is reduced or canceled, but the device complexity increases due to the multi-duct hollow structure
Solution Approach 1:
The patent applies thermal expansion by circulating heat transfer fluid through the hollow vane structure, causing controlled expansion of the vane material. This expansion generates counteracting forces that compensate for the aerodynamic bending forces, thereby reducing or canceling the net bending deformation of the vanes during operation.
Solution Approach 2:
The patent employs composite construction by integrating multiple functional ducts (central main duct and lateral ducts) within the hollow vane structure. This composite design allows simultaneous achievement of structural integrity, heat transfer functionality, and differential thermal expansion capabilities, resolving the complexity issue through multi-functional integration.
2Stability of the object's composition
If the vanes are designed with a hollow structure featuring a central main duct for heat transfer fluid circulation and lateral ducts between the main duct and the leading/trailing edges, then the bending deformation caused by aerodynamic forces is reduced or canceled, but the manufacturing complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the hollow vane structure into distinct duct sections (central main duct and lateral ducts) that can be manufactured separately and then assembled. This segmentation approach simplifies the manufacturing process compared to creating a single complex integrated hollow structure, as each duct section can be formed using standard fabrication techniques and then joined together.
Solution Approach 2:
The patent employs nesting by placing the lateral ducts within the structural framework defined by the central main duct. This nested arrangement allows efficient use of space within the hollow vane while simplifying manufacturing, as the inner lateral ducts can be installed within the outer shell defined by the main duct structure, reducing the need for complex multi-cavity molding or forging operations.
3Stability of the object's composition
If the main duct extends only in the central region of each blade section and the lateral ducts extend in the extreme regions, then the differential thermal expansion is optimized to counteract bending forces, but the heat transfer efficiency may be reduced due to limited fluid circulation coverage
Solution Approach 1:
The patent applies local quality by assigning different duct functions to different regions of the vane: the central main duct is positioned to provide primary structural support and generate the main thermal expansion force to counteract bending, while the lateral ducts in the extreme regions provide supplementary heat transfer and localized thermal management. This regional differentiation optimizes both the deformation compensation and heat transfer efficiency.
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 or cancels the bending deformation caused by aerodynamic forces, minimizing misalignment and wear, and allows for lighter construction by eliminating the need for additional static reinforcements.
Implementation Method 1
allowing differential thermal expansion to counteract aerodynamic bending forces
Implementation Method 2
a hollow and traversed by a main duct for the circulation of a heat transfer fluid cooled by circulating in the blade
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A guide vane (15) in an outer section of a turbofan engine contains oil cooling cavities which are located on one side of a main bending axis (Iz) of the vane (15) so that the differential thermal expansions compensate for the bending deformations caused by the aerodynamic forces exerted on the outer vane surface (16).