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CA-3158331-C - TEMPERATURE BARRIER COATING FOR RIM-ROTOR

CA3158331CCA 3158331 CCA3158331 CCA 3158331CCA-3158331-C

Abstract

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.

Inventors

  • Benoit Picard
  • Mathieu Picard
  • Jean-Sebastien Plante

Assignees

  • EXONETIK TURBO INC.

Dates

Publication Date
20260505
Application Date
20201127
Priority Date
20191128

Claims (9)

  1. WHAT IS CLAIMED IS: 1. A rim-rotor assembly comprising: an annular structure including a composite rim; a hub; blades projecting from the hub, tips of the blades contacting the annular structure, the blades configured to be loaded in compression against the annular structure; and a thermal barrier in the annular structure, the thermal barrier being continuous and defining at least part of a radially inward surface of the annular structure, radially-outward surfaces of the tips of the blades contacting the thermal barrier, the thermal barrier being a thermal barrier coating.
  2. 2. The rim-rotor assembly according to claim 1, wherein the annular structure includes a cooling ring between the composite rim and the thermal barrier.
  3. 3. The rim-rotor assembly according to claim 2, wherein the cooling ring defines cooling channels.
  4. 4. The rim-rotor assembly according to any one of claims 2 and 3, wherein the cooling ring includes a metallic ring.
  5. 5. The rim-rotor assembly according to any one of claims 2 and 3, wherein the cooling ring includes a thermal barrier coating on its inner face.
  6. 6. The rim-rotor assembly according to any one of claims 2 and 3, wherein the cooling ring is made of a composite of fibers in a conductive matrix.
  7. 7. The rim-rotor assembly according to any one of claims 1 to 6, wherein the blades are connected to the hub by sliding joints, and are biased into compression against the annular structure.
  8. 8. The rim-rotor assembly according to any one of claims 1 to 6, wherein the blades have a bottom segment connected to the hub, and a top segment against the annular structure, the bottom segment and the top segment interconnected by a translational joint.
  9. 9. The rim-rotor assembly according to any one of claims 1 to 8, wherein the composite rim includes carbon fibers in a matrix. 18 Date Re9ue/Date Received 2023-10-13 10. The rim-rotor assembly according to claim 9, wherein the matrix is made of one of cyanate ester, polyimide, and phtalonitrile. 11. The rim-rotor assembly according to any one of claims 1 to 10, wherein the thermal barrier coating includes a layer of yttrium-stabilized-zirconia or of yttrium aluminum garnet. 12. The rim-rotor assembly according to claim 11, wherein the layer has a thickness ranging between 300 μm up to 1500 μm, inclusively. 13. The rim-rotor assembly according to any one of claims 11 and 12, wherein the layer has a porosity level between 10 and 30%, inclusively. 14. The rim-rotor assembly according to any one of claims 11 to 13, wherein the layer is of yttrium-stabilized-zirconia, and has a density between 4.2 and 5.5 glee inclusively. 15. The rim-rotor assembly according to claim 11, wherein the layer is of yttrium aluminum garnet, and has a density between 3.2 and 4.2 glee inclusively. 16. The rim-rotor assembly according to any one of claims 11 to 15, wherein the thermal barrier includes a bond layer between the layer and a remainder of the annular structure. 17. The rim-rotor assembly according to claim 16, wherein the bond layer has a thickness ranging between 75 to 150 μm, inclusively. 18. The rim-rotor assembly according to any one of claims 16 and 17, wherein the bond layer is MCrAIY or NiAI. 19. The rim-rotor assembly according to any one of claims 16 to 18, wherein the bond layer has a porosity ranging between 5 to 15% inclusively. 20. The rim-rotor assembly according to any one of claims 11 to 19, wherein the thermal barrier includes an anti-friction layer radially inward of the layer. 21. The rim-rotor assembly according to claim 20, wherein the anti-friction layer has a thickness ranging between 25 to 100 μm, inclusively. 19 Date Re9ue/Date Received 2023-10-13 22. The rim-rotor assembly according to any one of claims 20 and 21, wherein the antifriction layer is boron nitride. 23. The rim-rotor assembly according to any one of claims 20 to 22, wherein the antifriction layer is at discrete separate zones opposite the tips of the blades. 24. The rim-rotor assembly according to any one of claims 11 to 19, wherein the tips of the blades include an anti-friction layer. 25. The rim-rotor assembly according to any one of claims 1 to 24, wherein the thermal barrier is annular. 26. The rim-rotor assembly according to claim 25, wherein the thermal barrier has a uniform thickness. 27. The rim-rotor assembly according to claim 25, wherein the thermal barrier has a non-uniform thickness. 28. The rim-rotor assembly according to claim 27, wherein the thermal barrier defines recesses for receiving the tips of the blades. 29. The rim-rotor assembly according to claim 27, wherein the thermal barrier is thicker opposite the tips of the blades. 30. The rim-rotor assembly according to any one of claims 1 to 29, wherein the thermal barrier includes a conduction-reduction coating defining a part of the radially inward surface of the annular structure against which radially-outward surfaces of the tips of the blades contact the annular structure. 31. The rim-rotor assembly according to any one of claims 1 to 30, wherein the thermal barrier includes a convection-heat-transfer-reduction coating defining a part of the radially inward surface that is exposed to hot gases flowing through the blades and the annular structure. Date Re9ue/Date Received 2023-10-13

Description

TEMPERATURE BARRIER COATING FOR RIM-ROTOR CROSS-REFERENCE TO RELATED APPLICATION The present disclosure claims the priorities of United States Patent Application Serial No. 62/941,832, filed on November 28, 2019, of United States Patent Application Serial No. 62/944,047, filed on December 5, 2019, and of United States Patent Application Serial No. 62/948,473, filed on December 16, 2019. FIELD OF THE DISCLOSURE The present disclosure relates to rim-rotor turbomachinery where the turbine is radially supported by a reinforced rim-rotor, for instance of composite such as carbon, that empowers the use of ceramics. BACKGROUND OF THE INVENTION Mobile applications require power sources that are compact, have minimal weight and volume. In addition, due to a variety of factors including global warming issues, fossil fuel availability and environmental impacts, crude oil price and availability issues, efficiency of a power source is a focus in the transportation industry. For the transportation industry, especially air transportation where reliability is critical, turbines are recognized as offering one of the best solutions. In a turbine, as a general principle, the higher the turbine inlet temperature is, the more efficient the turbine will be. Recuperated Brayton cycles are recognized to provide a better efficiency than simple Brayton cycle. A challenge with increasing the temperature of a recuperated Brayton cycle lies in the turbine itself, where typical alloys require large amounts of cooling to be able to withstand high gas temperatures. This is even more challenging for small scale turbines(< 1 MW) where film cooling is hard to implement and significantly reduces cycle efficiency. Attempts have been made to use ceramics, such as silicon nitride and silicon carbide, for gas turbines since these materials can withstand high temperatures, but due to their brittleness they show reliability issues. Prior attempts have been made to build ceramic turbines 1 Date Re9ue/Date Received 2023-10-13 contained in a rim-rotor, such as U.S. Patent No. 4,017,209, but such attempts do not propose a viable cooling solution for some materials such as composites. A composite rim-rotor is limited by glass transition for carbon-polymer composites, or oxidation for carbon-carbon composites. These attempts have also been limited to purely axial turbine designs, which do not take full advantage of the rim-rotor that could be used for hub-less designs allowing inversed radial, axial or mixed flow configurations that optimize the temperature distribution of the engine packaging by keeping the hot gases on one single side of the turbine wheel, therefore separating structural and thermal loops. Furthermore, when considering rim-rotor machinery, there is a challenge in matching the displacement of the rim-rotor to the displacement of a rigid hub. The rim-rotor also needs to be thermally insulated from the hot combustion gases, with ceramics being a choice candidate due to their low conductivity and high temperature resistance. Accordingly, there is a need for a compact turbine that can operate at high air preheat temperatures with limited instabilities or failures, that could be used in industrial (furnaces, heaters) and power applications such as distributed CHP, aerospace and automotive applications. For maximum efficiency and emissions benefits in power applications, this turbine would have the capacity of being used with rim-rotor ceramic turbomachinery allowing high combustion temperatures, and hence high cycle efficiency. SUMMARY Therefore, in accordance with an aspect of the present disclosure, there is provided a rimrotor assembly comprising: an annular structure including a composite rim; a hub; blades projecting from the hub, tips of the blades contacting the annular structure, the blades configured to be loaded in compression against the annular structure; and 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. Further in accordance with the aspect, for example, the annular structure includes a cooling ring between the composite rim and the thermal barrier. Still further in accordance with the aspect, for example, the cooling ring defines cooling channels. 2 WO 20211102582 PCTICA20201051625 Still further in accordance with the aspect, for example, the cooling ring includes a metallic ring. Still further in accordance with the aspect, for example, the cooling ring is made of a thermal barrier coating. Still further in accordance with the aspect, for example, the cooling ring is made of a composite of fibers in a conductive matrix. Still further in accordance with the aspect, for example, the blades are connected to the hub by sliding joints, and are biased into compression against the annular structure. Still further in accordance with t