Aircraft Turbine Vane Recessed Tip Geometry Optimization

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Solution Overview

Problem

The deposition of Stellite anti-wear coatings on turbomachine blades is prone to cracking due to geometric confinement, reduced visibility, and manual welding, leading to increased blade scrap rates.

Innovation Solution

Optimizing the geometric parameters of the recessed tip on the blade's external platform, including a concave cylindrical surface with specific dimensions and configurations, to reduce sudden geometry variations and stress, thereby minimizing the risk of cracks during coating deposition.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the recessed tip geometry is conventional (with sharp transitions), then the blade structure is simple, but the anti-wear coating is prone to cracking during deposition

Engineering Contradiction:
Improvecoating integrityVSAvoidrecessed tip geometry
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention replaces sharp geometric transitions with curved surfaces in the recessed tip region. Specifically, a first curved surface replaces the sharp transition between the recessed tip and the blade body, while a second curved surface replaces the sharp transition between the recessed tip and the lip. These curved surfaces eliminate stress concentration points that cause coating cracks during deposition, thereby improving coating integrity without significantly complicating the manufacturing process.

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Ease of manufacture

If manual welding is used for Stellite deposition, then the coating can be applied to complex geometries, but the process is time-consuming and produces high scrap rates

Engineering Contradiction:
Improvecoating deposition capabilityVSAvoidblade production rate
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The invention modifies the geometric parameters of the recessed tip region by introducing specific curvature radii (R1 for the first curved surface, R2 for the second curved surface) and dimensional relationships (h1 ≥ 1.5×e, where h1 is the height of the curved surface and e is the lip thickness). These parameter changes create a geometry that is more amenable to automated coating processes, reducing the time-consuming nature of manual welding while maintaining the ability to coat complex geometries effectively.

Inventive Principle:
Principle #35Parameter changes

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

The optimized geometry reduces stress by 35% in the recessed point, as confirmed by Stellite deposition simulation, enhancing the robustness of the blade design without excessive mass and minimizing crack formation.

Implementation Method 1

The optimized geometry reduces stress by 35% in the recessed point, as confirmed by Stellite deposition simulation, enhancing the robustness of the blade design without excessive mass and minimizing crack formation.

Methodology Applied
Scientific EffectStress concentration reduction through geometric optimization:

Data Source

PatentEP4100624B1Vane for an aircraft turbine engine
Publication Date: 2023.12.27 SAFRAN AIRCRAFT ENGINES SAS
  • EP4100624B1 patent drawingFigure 1
  • EP4100624B1 patent drawingFigure 2~3d
  • EP4100624B1 patent drawingFigure 4

AI summary

Disclosed is a rotor vane (10) for an aircraft turbine engine, this vane comprising a blade (16) extending between an inner platform (19) and an outer platform (20) which carries at least one projecting lip (31, 32), the blade having a lower surface (16a) and an upper surface and the outer platform comprising, on the side of the lower and upper surfaces, lateral edges (21, 22) configured to cooperate in a form-fitting manner with complementary lateral edges (22, 21) of adjacent vanes, these lateral edges each comprising an anti-wear coating (36), one of these lateral edges forming a hollow tip (P) comprising a bowl (38) for receiving the coating and further comprising a first concave cylindrical surface portion (40), the geometric dimensions of which are optimised to limit the risk of cracks appearing when the coating is applied.