Composite Turbine Blade Leading Edge Shield Geometry
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Solution Overview
Problem
Existing leading edge shields for turbomachine blades made of composite materials are prone to separation during impacts, leading to aerodynamic degradation and increased risk of damage, especially due to the ingestion of small birds, which compromises the protection and performance of the blades.
Innovation Solution
A leading edge shield with a specific geometry, comprising an intrados fin, an extrados fin, and a thicker central part, where the extrados fin has varying lengths and angles to reduce separation and distribute stress, enhancing the protective effect and aerodynamic stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If a thin extrados fin is used in the leading edge shield, then the weight is reduced, but the fin separates easily during impacts
Solution Approach 1:
The patent applies local quality by varying the thickness of the extrados fin along its length. The fin is thickest at the root for strong attachment, gradually thinning toward the tip to reduce weight. This gradient thickness distribution allows the fin to maintain both low weight and high reliability - the thick root region resists separation during impacts while the overall fin remains lightweight.
2Strength
If the leading edge shield geometry is optimized for protection, then impact resistance is improved, but aerodynamic performance deteriorates due to complex shapes
Solution Approach 1:
The leading edge shield is segmented into distinct functional zones: a thick central part for impact absorption, and thinner fin regions for attachment and aerodynamic profiling. This segmentation allows each zone to be optimized independently - the central part provides protection while the fins maintain aerodynamic efficiency, resolving the contradiction between protection and aerodynamic performance.
Solution Approach 2:
The patent resolves the geometry complexity issue by transitioning from a two-dimensional planar shield to a three-dimensional form with varying thickness. The shield maintains a simple external aerodynamic contour while incorporating internal thickness variations - thick in the central protective region, thin at the fins - allowing both aerodynamic performance and impact resistance to be optimized without complex external shaping.
3Object-affected harmful factors
If the shield follows a complex blade shape, then protection coverage is improved, but manufacturing complexity increases
Solution Approach 1:
The patent uses parameter changes by varying the thickness parameter of the shield rather than changing its external contour. The thickness parameter transitions from thick in the central region to thin at the fins, allowing the shield to conform to complex blade shapes and provide complete protection coverage while maintaining simple manufacturing. The external aerodynamic profile remains straightforward, avoiding complex geometry in the primary load-bearing surfaces.
Data Source
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AI summary
The invention relates to a blade (16) comprising a blade body (18) made of a fibre-reinforced organic matrix composite material and a leading edge shield (20) made of a material having better point impact resistance than the composite material of the blade body, the leading edge shield (20) being assembled to the blade body (18) and having a pressure side fin (32) and a suction side fin (30) connected by a thicker central portion (34), the blade (16) comprising an aerodynamic airstream height and a chord length, the suction side fin (30) having a first length (36) projected onto the chord comprised between 10 and 18% of the chord length, the first length (36) being disposed between 70 and 80% of the height of the aerodynamic airstream, a second length projected onto the chord comprised between 18 and 26% of the chord length, the second length being disposed between 85 and 95% of the height of the aerodynamic airstream, and a third length projected onto the chord between the first length and the second length, the third length being disposed at 100% of the height of the aerodynamic airstream. Turbine engine comprising the blade.