CMC Cooling Channel Core for Gas Turbine Casting
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Solution Overview
Problem
Existing methods for forming long, narrow cooling channels in cast components, such as those for gas turbine engines, face issues with ceramic cores becoming weak and brittle due to high preheat temperatures, leading to dimensional instability and fracturing during single crystal metal casting.
Innovation Solution
A method involving a ceramic matrix composite (CMC) elongated core reinforced with ceramic fibers is used, where a shell mold is formed over the CMC core arrangement, and the pattern-forming material is removed, allowing molten metal to fill the cavity and solidify, with the CMC core later being leached out to create a stable and functional cooling channel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If long, narrow ceramic cores are used to form cooling channels during casting, then cooling channels can be formed in the cast component, but the ceramic cores become weak and brittle at high preheat temperatures, leading to dimensional instability and fracturing
Solution Approach 1:
The patent applies composite materials by combining ceramic matrix with reinforcement fibers (such as alumina fibers, zirconia fibers, or silicon carbide fibers) to create a reinforced ceramic core. This composite structure provides both the cooling channel formation capability and the thermal/mechanical strength needed to withstand high preheat temperatures without fracturing or becoming dimensionally unstable.
Solution Approach 2:
The patent changes the material parameters of the ceramic core by incorporating reinforcement fibers at specific concentrations and orientations. This modifies the core's mechanical properties, strength, and thermal stability, enabling it to maintain dimensional accuracy during the high-temperature casting process while still allowing cooling channel formation.
2Manufacturing precision
If single crystal metal casting is used to form gas turbine engine components, then high precision and structural integrity are achieved, but the very high preheat temperatures required cause ceramic cores to become too weak and brittle
Solution Approach 1:
The reinforced ceramic core uses composite materials with ceramic matrix and reinforcement fibers that can withstand the very high preheat temperatures required for single crystal casting. The composite structure maintains both the precision needed for single crystal formation and the strength to resist thermal and mechanical stresses during the casting process.
Solution Approach 2:
The reinforced ceramic core is prepared beforehand with sufficient strength and dimensional stability to cushion against the harsh conditions of single crystal casting. The reinforcement fibers are incorporated in advance to provide immediate protection against thermal shock, mechanical stress, and dimensional changes during the high-temperature casting operation.
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 approach ensures dimensional stability and effective heat management by maintaining the structural integrity of the CMC core during high-temperature exposure, enabling the formation of reliable and efficient cooling channels within cast components.
Implementation Method 1
The leaching out or etching comprises advancing a wet etchant into the hollow passage to facilitate leaching out and or etching of the CMC elongated core
Implementation Method 2
The leaching out or etching comprises advancing a wet etchant into the hollow passage to facilitate leaching out and or etching of the CMC elongated core
Implementation Method 3
forming a shell mold over a pattern-ceramic matrix composite (CMC) elongated core arrangement to define a cavity in the shell mold
Implementation Method 4
The pattern-forming material in the cavity is replaced with metal via a casting process to form the cast component with the CMC elongated core disposed therein defining the cooling channel
Implementation Method 5
The CMC elongated core is removed from the cast component to open the cooling channel for fluid communication
Data Source
Figure 1~2
Figure 3~5
Figure 4
AI summary
The present disclosure relates generally to cast components, and more particularly to methods for fabricating cast components with cooling channels, such as, for example, for a gas turbine engine or the like.