Turbomachine Blade Core Assembly with Bulge Anchoring
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Solution Overview
Problem
The manufacturing of turbine blades with complex shapes and advanced aerodynamic features, such as the 'offset of the cuts at the top' design, faces challenges in core assembly due to the small size and intricate geometry, leading to issues with core stability, crack formation, and high scrap rates during the lost-wax casting process.
Innovation Solution
A foundry core assembly comprising a first core element for forming internal cavities and a second core element for forming the bathtub cavity, where the central cavity inner core has a bulge adjacent to the trailing edge cavity core, allowing for increased anchoring depth and thickness of connecting rods, reducing the risk of cracks and improving the manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional core assembly methods are used for advanced aerodynamic blade designs, then manufacturing complexity increases, but core stability and reliability deteriorate due to small size and intricate geometry
Solution Approach 1:
The patent applies local quality by creating a bulge specifically at the distal end of the central cavity inner core. This localized geometric modification concentrates the anchoring function at a specific location, providing enhanced connecting rod retention precisely where needed for advanced aerodynamic blade designs without compromising overall core stability
Solution Approach 2:
The bulge is pre-formed on the central cavity inner core before assembly with other core elements. This preliminary action ensures that the anchoring structure is already in place to receive and secure the connecting rod, preventing core movement and crack formation before the casting process begins
2Ease of manufacture
If connecting rods are used to assemble core elements, then core elements can be held together, but crack formation occurs due to insufficient anchoring depth in small-scale complex geometries
Solution Approach 1:
The bulge creates a localized region of increased thickness at the distal end of the central cavity inner core. This local geometric enhancement provides sufficient anchoring depth for connecting rods in small-scale complex geometries, enabling secure assembly without causing stress concentrations that lead to cracking
Solution Approach 2:
The bulge acts as a pre-prepared cushioning structure that absorbs and distributes the mechanical stresses from connecting rod anchoring. By providing extra material thickness in advance, it prevents stress concentrations that would otherwise cause cracks during the casting process
3Manufacturing precision
If core elements are positioned with extreme precision in the shell, then cavity geometry is reproduced accurately, but assembly complexity and difficulty increase
Solution Approach 1:
The bulge at the distal end of the central cavity inner core creates a natural positioning feature that aligns with the showerhead injection direction. This geometric equipotential feature ensures automatic alignment and precise positioning of core elements during assembly, reducing the complexity of achieving extreme precision in the shell
Solution Approach 2:
The bulge is pre-formed on the core element to provide a locating feature before assembly. This preliminary geometric preparation ensures that when core elements are assembled in the shell, they automatically achieve the required extreme precision for cavity geometry reproduction without complex positioning procedures
Data Source
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AI summary
The invention relates to a foundry core (30) for manufacturing a blade (1) of a turbomachine (1) having a tip section offset, comprising a core element (31) for forming various internal cavities (19a-19e), said core element comprising a leading-edge cavity internal core (31a), central cavity internal cores (31b, 31c, 31d) and a trailing-edge cavity internal core (31e), characterized in that the internal core for the central cavity (31d) adjacent to the internal core (31e) for the trailing-edge cavity has a bulge (34) extending toward the core (31a) for the leading-edge cavity.