Asymmetric Leading Edge Shield for Turbine Blades
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Solution Overview
Problem
The existing leading edge shields for turbine engine blades, made of metallic materials to protect against impacts, increase mass and inertia due to the additional length of the intrados fin, which is not uniformly exposed to impacts.
Innovation Solution
A leading edge shield design where the intrados fin is longer than the extrados fin in the first segment closer to the blade root, but equal to or less than the extrados fin in the second segment, reducing mass and inertia while maintaining protection, with the intrados fin depth remaining significant in the second segment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the intrados fin is extended in length to protect the lower surface of the blade, then the protection capability is improved, but the mass and inertia of the shield increase significantly
Solution Approach 1:
The patent applies local quality by varying the intrados fin length along the height of the shield. The first segment (lower portion) has a longer intrados fin to provide enhanced protection where impacts are most severe, while the second segment (upper portion) has a reduced intrados fin length where impact exposure is lower. This localized differentiation optimizes protection capability while minimizing unnecessary mass addition in regions where full protection is not required.
2Loss of energy
If the intrados fin length is increased to distribute impact energy over a larger area, then the energy dissipation is improved, but the shield mass and rotational inertia increase
Solution Approach 1:
The patent implements local quality by providing extended intrados fin length in the first segment where impact energy dissipation is most critical, while reducing the intrados fin length in the second segment where energy dissipation requirements are lower. This ensures adequate energy distribution and dissipation capability is maintained in high-risk zones without unnecessarily increasing overall shield mass.
3Reliability
If the shield structure is made asymmetric with longer intrados fin for lower surface protection, then the protection effectiveness is improved, but the device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the shield into two distinct segments along its height: a first segment with extended intrados fin length for maximum protection, and a second segment with reduced intrados fin length. This segmented approach allows the structure to adapt to varying impact exposure levels at different heights while maintaining a relatively simple overall geometry that is easier to manufacture and install compared to fully complex asymmetric designs.
Data Source
Figure 1~2A
Figure 2B~4
AI summary
The invention relates to the field of turbomachine blades, and more specifically to a leading edge shield (32) for a turbomachine blade (16), which comprises a lower canopy fin (34) and an upper canopy fin (36), each extending in the height and length direction and connected together along their height, the lower canopy fin (34) having a greater length than the upper canopy fin (36) over a first segment (SI) of the leading edge shield (32), and a length equal to or lower than the upper canopy fin (36) over a second segment (S2) of the leading edge shield (32).