Ceramic Turbine Airfoil Internal Cooling via Sacrificial Cores
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Solution Overview
Problem
Gas turbine engines face inefficiencies due to the need for compressor bleed cooling, which penalizes engine efficiency by relying on pressure differential, and there is a challenge in enhancing thermal resistance at the compressor exit and turbine inlet to reduce the need for such cooling.
Innovation Solution
The method involves fabricating ceramic airfoil pieces with internal cooling circuits by arranging preceramic layers around sacrificial core elements, converting them to ceramic, and removing the cores to create passages for cooling, which enhances thermal resistance and reduces the need for compressor bleed cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If compressor bleed cooling is used to cool turbine components, then thermal resistance is improved, but engine efficiency deteriorates due to pressure differential penalties
Solution Approach 1:
The turbine component is segmented into multiple walls with internal cooling circuits, allowing independent cooling zones that can be optimized for different thermal loads while maintaining overall component integrity
Solution Approach 2:
The cooling approach transitions from external bleed air cooling to internal dimensional cooling circuits embedded within the component walls, adding a thermal management dimension within the component structure itself rather than relying on external airflow
2Temperature
If ceramic materials are used to enhance thermal resistance, then temperature resistance is improved, but manufacturing complexity increases due to fabrication challenges
Solution Approach 1:
Cooling circuits are built into the ceramic component during the manufacturing process itself, rather than attempting to add cooling features after fabrication. The preceramic layers are formed with embedded cooling channel geometries before ceramic conversion
Solution Approach 2:
The component uses composite construction with preceramic polymer layers reinforced with fibers, allowing complex internal cooling circuit geometries to be formed more easily than in monolithic ceramics, then converted to ceramic matrix composite for high-temperature service
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 enhances the thermal resistance of turbine components, reducing the need for compressor bleed cooling and improving engine efficiency by integrating internal cooling circuits within the ceramic airfoil pieces.
Implementation Method 1
converting the preceramic layers to ceramic
Implementation Method 2
the removal of the one or more sacrificial core elements includes thermally removing the carbon elements
Data Source
AI summary
A method of fabricating a ceramic turbine engine article includes building a wall of the article from preceramic layers, wherein the building includes arranging the preceramic layers around one or more sacrificial core elements, converting the preceramic layers to ceramic, and removing the one or more sacrificial core elements to leave one or more cavities in the wall.