Design of an efficient space constrained diffuser for supercritical CO2 turbines
Paper
Paper/Presentation Title | Design of an efficient space constrained diffuser for supercritical CO2 turbines |
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Presentation Type | Paper |
Authors | Keep, Joshua A., Head, Adam J. and Jahn, Ingo H. |
Journal or Proceedings Title | Journal of Physics: Conference Series |
Journal Citation | 821 (1) |
Article Number | 012026 |
Number of Pages | 10 |
Year | 2016 |
Publisher | IOP Publishing |
ISSN | 1742-6588 |
1742-6596 | |
Digital Object Identifier (DOI) | https://doi.org/10.1088/1742-6596/821/1/012026 |
Web Address (URL) of Paper | https://iopscience.iop.org/article/10.1088/1742-6596/821/1/012026/meta |
Web Address (URL) of Conference Proceedings | https://iopscience.iop.org/issue/1742-6596/821/1 |
Conference/Event | 1st International Seminar on Non-Ideal Compressible-Fluid Dynamics for Propulsion & Power |
Event Details | 1st International Seminar on Non-Ideal Compressible-Fluid Dynamics for Propulsion & Power Delivery In person Event Date 19 to end of 20 Oct 2016 Event Location Varenna, Italy |
Abstract | Radial inflow turbines are an arguably relevant architecture for energy extraction from ORC and supercritical CO2 power cycles. At small scale, design constraints can prescribe high exit velocities for such turbines, which lead to high kinetic energy in the turbine exhaust stream. The inclusion of a suitable diffuser in a radial turbine system allows some exhaust kinetic energy to be recovered as static pressure, thereby ensuring efficient operation of the overall turbine system. In supercritical CO2 Brayton cycles, the high turbine inlet pressure can lead to a sealing challenge if the rotor is supported from the rotor rear side, due to the seal operating at rotor inlet pressure. An alternative to this is a cantilevered layout with the rotor exit facing the bearing system. While such a layout is attractive for the sealing system, it limits the axial space claim of any diffuser. Previous studies into conical diffuser geometries for supercritical CO2 have shown that in order to achieve optimal static pressure recovery, longer geometries of a shallower cone angle are necessitated when compared to air. A diffuser with a combined annular-radial arrangement is investigated as a means to package the aforementioned geometric characteristics into a limited space claim for a 100kW radial inflow turbine. Simulation results show that a diffuser of this design can attain static pressure rise coefficients greater than 0.88. This confirms that annular-radial diffusers are a viable design solution for supercritical CO2 radial inflow turbines, thus enabling an alternative cantilevered rotor layout. |
Contains Sensitive Content | Does not contain sensitive content |
ANZSRC Field of Research 2020 | 4017. Mechanical engineering |
Byline Affiliations | University of Queensland |
Delft University of Technology, Netherlands | |
School of Engineering |
https://research.usq.edu.au/item/z2153/design-of-an-efficient-space-constrained-diffuser-for-supercritical-co2-turbines
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Keep_2017_J._Phys.__Conf._Ser._821_012026.pdf | ||
License: CC BY 3.0 | ||
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