Rim-Rotor Thermal Barrier Coating for High-Temperature Turbomachinery
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Solution Overview
Problem
Current rim-rotor turbomachinery faces challenges in achieving high efficiency and reliability at high temperatures due to material limitations, particularly with ceramic materials used in small-scale turbines, which are brittle and require extensive cooling, and struggle to match displacement with rigid hubs, limiting their application in compact, high-temperature environments.
Innovation Solution
A rim-rotor assembly featuring a composite rim with a thermal barrier coating, a cooling ring, and sliding joints, where the thermal barrier coating is made of yttrium-stabilized-zirconia or yttrium aluminum garnet, and the cooling ring is designed to manage heat flux and structural integrity, allowing for high-temperature operation with reduced instability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If ceramic materials are used in small-scale turbines, then high temperature resistance is improved, but brittleness and requirement for extensive cooling worsen
Solution Approach 1:
The patent uses composite materials combining ceramic matrix composites (CMC) for the rim-rotor with metallic alloys for the hub and blade roots. This composite approach allows the ceramic components to withstand high temperatures while the metallic portions provide ductility and structural support, reducing overall brittleness and cooling requirements.
Solution Approach 2:
The patent introduces a thermal barrier coating as an intermediary layer between the ceramic rim-rotor and the hot combustion gases. This coating protects the ceramic material from direct thermal exposure, reducing thermal stress and preventing thermal shock, thereby improving reliability without requiring extensive cooling.
2Temperature
If rim-rotor is thermally insulated from hot combustion gases, then temperature resistance is improved, but displacement matching with rigid hub worsens
Solution Approach 1:
The patent employs sliding joints between the ceramic rim-rotor and the metallic hub, allowing relative movement and displacement accommodation. This dynamic interface enables the rim-rotor to expand and contract thermally while maintaining proper alignment with the hub, resolving the displacement matching issue.
Solution Approach 2:
The patent uses a flexible thermal barrier coating that can accommodate thermal expansion and displacement differences between the ceramic rim-rotor and the rigid hub. This flexible interface maintains thermal insulation while allowing necessary movements.
3Strength
If typical alloys are used in turbine, then structural strength is improved, but cooling requirements increase
Solution Approach 1:
The patent replaces typical metallic alloys with ceramic matrix composites (CMC) for the rim-rotor components. CMC materials provide comparable or superior structural strength at high temperatures while having much lower thermal conductivity, dramatically reducing cooling air requirements and improving overall efficiency.
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 solution enables efficient operation at high temperatures with reduced instability and extended lifespan, optimizing temperature distribution and structural integrity, thereby enhancing the efficiency and reliability of rim-rotor turbomachinery for various applications.
Implementation Method 1
a thermal barrier in the annular structure, the thermal barrier defining at least part of a radially inward surface of the annular structure, the tips of the blades contacting the thermal barrier, the thermal barrier being a thermal barrier coating
Implementation Method 2
the annular structure includes a cooling ring between the composite rim and the thermal barrier
Data Source
AI summary
A rim-rotor assembly has an annular structure including a composite rim and a hub. Blades project from the hub, tips of the blades contacting the annular structure, the blades configured to be loaded in compression against the annular structure. A thermal barrier is in the annular structure, the thermal barrier defining at least part of a radially inward surface of the annular structure. The tips of the blades contact the thermal barrier, the thermal barrier being a thermal barrier coating.