Variable Fillet Turbine Vanes for Stress and Flow Optimization
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Solution Overview
Problem
Existing turbine vanes with uniform large fillets are inefficient in managing stress concentrations and aerodynamic flow, as they do not allow for optimal variation in fillet size and shape to address thrust and clearance issues effectively.
Innovation Solution
The design introduces variable fillets with distinct sizes and shapes along the airfoil, including a tapered and uniform portion, to address stress concentrations and improve aerodynamic flow by reducing weight and allowing additional clearance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If uniform large fillets are used at all locations along the airfoil, then stress concentrations at leading and trailing edges are addressed, but weight increases and aerodynamic flow is impaired
Solution Approach 1:
The patent applies different fillet sizes at different locations along the airfoil. Larger fillets are positioned at the leading and trailing edges where stress concentrations occur, while smaller fillets are used in intermediate regions. This local differentiation allows stress relief where needed without unnecessarily adding weight throughout the entire vane structure.
2Strength
If uniform large fillets are used at all locations along the airfoil, then stress concentrations at leading and trailing edges are addressed, but aerodynamic flow is impaired
Solution Approach 1:
By concentrating larger fillets only at the leading and trailing edges where structurally necessary, and using smaller fillets in the remaining gas-path regions, the design maintains stress relief capability while minimizing interference with aerodynamic flow through the turbine vane.
3Weight of moving object
If variable fillet sizes are used along the airfoil, then weight is reduced and aerodynamic flow is improved, but manufacturing complexity increases
Solution Approach 1:
The fillet structure is segmented into multiple regions with different characteristic sizes. This segmentation into discrete zones (larger fillets at edges, smaller fillets in between) makes the variable geometry more manageable for manufacturing while still achieving the weight reduction and aerodynamic benefits of non-uniform fillet distribution.
Data Source
Figure 1A
Figure 1B
Figure 2~3A
AI summary
An airfoil extends between radially inner and radially outer platforms. The airfoil extends between a leading edge and a trailing edge, and merges into facing surfaces of the radially inner and outer platforms. A variable fillet merges a facing surface of one of the radially inner and outer platforms into a wall of the airfoil. The variable fillet has a length extending away from a surface of the airfoil and a height extending away from the facing surface of at least one of the radially inner and outer platforms outwardly on to the airfoil. The variable fillet has a greater length at one of the leading edge and the trailing edge. A spaced portion has a shorter length at locations spaced from at least one of the leading and trailing edges. A mid-turbine frame and a gas turbine engine are also disclosed.