Turbomachine Blade Cooling Core with Spherical Recesses

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Solution Overview

Problem

The manufacturing of turbomachine blades with internal cooling cavities faces challenges in achieving optimal cooling performance due to geometric and dimensional limitations in lost wax molding, particularly for blades with strong curvature, leading to inefficiencies in airflow distribution and increased risk of defects during core injection.

Innovation Solution

A core and mold design featuring convex and concave curved faces with spherical recesses, aligned along specific symmetry axes, allows for improved airflow distribution and simplifies the manufacturing process by minimizing the number of core nuclei and avoiding material filling defects, enabling effective cooling even in complex geometries.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If bridges are used as flow restrictors in the cooling cavity, then airflow distribution is improved, but the core geometry becomes complex requiring multi-part molds and increasing manufacturing difficulty

Engineering Contradiction:
Improveairflow distributionVSAvoidcore geometry
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The invention extracts the flow restriction function from complex bridge structures and concentrates it into simple spherical recesses on the core surface. These recesses are formed directly during core injection molding without requiring additional bridge components or complex multi-part molds, thus maintaining airflow distribution while simplifying core geometry and manufacturing.

Inventive Principle:
Principle #2Taking out (Extraction)

2Ease of manufacture

If concave shapes are used in the cooling cavity, then manufacturing is simplified, but airflow distribution deteriorates due to vortex formation

Engineering Contradiction:
Improvecore productionVSAvoidairflow distribution
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The invention uses spherical recesses with controlled curvature instead of conventional concave shapes. The spherical geometry with specific radius ratios (r1/r2 between 0.5-2.0) minimizes vortex formation while maintaining ease of manufacture through simple injection molding, thus resolving the contradiction between manufacturing simplicity and airflow distribution.

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Adaptability or versatility

If multi-part molds are used to manufacture complex cores, then core geometry flexibility is improved, but positioning precision and productivity deteriorate

Engineering Contradiction:
Improvecore geometry flexibilityVSAvoidpositioning precision
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The invention merges the core manufacturing into a single-part mold that directly forms spherical recesses during injection molding. This eliminates the need for multi-part molds and their associated positioning issues, while maintaining core geometry flexibility through the simplicity of the single-part molding process.

Inventive Principle:
Principle #5Merging (Combining)

4Productivity

If core injection molding is used, then productivity is improved, but defects appear due to material filling issues

Engineering Contradiction:
Improvemanufacturing speedVSAvoiddefect rate
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The invention changes the geometric parameters of the core surface by introducing spherical recesses with specific dimensions (radius r1 and r2 with controlled ratios). This parameter optimization improves material flow during injection molding, reducing defects while maintaining high productivity of the injection molding process.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3475011B1Turbomachine blade cooling circuit
Publication Date: 2022.03.30 SAFRAN AIRCRAFT ENGINES SAS
  • EP3475011B1 patent drawingFigure 1
  • EP3475011B1 patent drawingFigure 2~3
  • EP3475011B1 patent drawingFigure 4~5

AI summary

The invention relates to a core (18) intended for the production of a turbomachine blade by means of lost-wax moulding, said core (18) comprising a convex outer first face (20) and a concave outer second face (21), characterised in that the first and second faces (20, 21) comprise a plurality of recesses (24a, 24b), each recess (24a, 24b) comprising a spherical portion (25).