Turbomachine Fan Blade Tip Segmentation for Clearance Control
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Solution Overview
Problem
Turbomachine rotary blower dawns experience self-engagement issues due to deformation under centrifugal and aerodynamic forces, leading to potential damage and aerodynamic performance degradation.
Innovation Solution
The introduction of a metal reinforcement part with a metallic projection of prescribed wear at the dawn head, designed to detach partially under tangential friction, preventing self-engagement and allowing for progressive wear that maintains aerodynamic efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the radial clearance at the blade tip is reduced to improve aerodynamic performance, then aerodynamic efficiency increases, but the blade becomes more prone to self-engagement and contact damage with the abradable material
Solution Approach 1:
The blade tip is segmented into a rigid main body and a frangible section that can detach. The frangible section includes a groove filled with resin that creates a weakened zone, allowing the tip to break away upon contact with the abradable material, preventing self-engagement while maintaining small clearance for aerodynamic efficiency
Solution Approach 2:
The mechanical properties of the blade tip are changed by creating a frangible zone with specific strength characteristics. The groove depth and resin material are designed to provide controlled brittleness, enabling the tip to transition from a fully rigid structure to one with localized weakness that facilitates detachment under contact stress
2Reliability
If the radial clearance at the blade tip is increased to prevent contact with the abradable material, then blade reliability improves, but aerodynamic performance deteriorates due to increased leakage flow
Solution Approach 1:
The blade tip is divided into a rigid main body that maintains aerodynamic shape and a frangible section that can detach. This segmentation allows the majority of the blade to operate at optimal clearance for aerodynamic efficiency while only a small sacrificial portion provides contact protection
Solution Approach 2:
The frangible section acts as a disposable protective element that is intentionally designed to fail first during contact events. By sacrificing this small portion of the blade tip, the expensive main blade body and engine components are protected from damage, and aerodynamic performance is maintained
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 solution effectively reduces the criticality of self-engagement, limits damage to the dawn head, and improves aerodynamic performance by allowing for reduced gap settings between the dawn and the abradable material.
Implementation Method 1
configured to detach at least partially in the presence of tangential friction going in the second thickness direction against the metal part of the blade head
Implementation Method 2
The wear of the prescribed metal wear projection of the blade head during its possible rotation against the abradable material of the fan casing may be progressive
Implementation Method 3
when the blade operates at high speed, it deforms under the centrifugal effect and aerodynamic forces
Implementation Method 4
a fixed casing surrounding them with a clearance between the blades and the casing, which is internally covered with an abradable material that can be planed by the rotating blade tips
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
The present invention relates to a turbomachine rotary-fan blade (2), comprising a body (20) made of a composite material, a metal reinforcement part (3) comprising a metal upstream nose (31), characterised in that the metal upstream nose (31) comprises, at least on the metal part (27b) of the blade tip, a recess (4) of longitudinally tapering thickness (AX), delimiting on the metal part (27b) over a height (H) at least one metal projection (5) with prescribed wear, which has a longitudinally tapering thickness and which is configured to detach at least partially in the presence of tangential friction in the second thickness direction (EP) against the metal part (27b), the recess (4) and the metal projection (5) with prescribed wear extending the first metal fin (32) and/or the second metal fin (33) and/or the upstream edge (22) of the body (20) made of composite material.