Details
| Original language | English |
|---|---|
| Title of host publication | ASME Turbo Expo 2022: Turbomachinery Technical Conference and Exposition |
| Subtitle of host publication | Turbomachinery - Axial Flow Turbine Aerodynamics; Deposition, Erosion, Fouling, and Icing; Radial Turbomachinery Aerodynamics |
| Publisher | American Society of Mechanical Engineers(ASME) |
| Number of pages | 9 |
| ISBN (electronic) | 9780791886106 |
| Publication status | Published - 28 Oct 2022 |
| Event | ASME Turbo Expo 2022: Turbomachinery Technical Conference and Exposition, GT 2022 - Rotterdam, Netherlands Duration: 13 Jun 2022 → 17 Jun 2022 |
Publication series
| Name | Proceedings of the ASME Turbo Expo |
|---|---|
| Volume | 10B |
Abstract
Industrial processes, small-scale power plants or internal combustion engines produce a high amount of waste heat as a by-product. The Organic Rankine Cycle (ORC) technology allows to recover that heat more efficiently compared to steam/water in conventional Clausius-Rankine cycles. For a comparably efficient and economical operation over a wide range of operating conditions, partial admission control appears to be a well-suited design option for ORC turbines. However, accurate numerical performance prediction of a partial admitted turbine stage is challenging and requires full annulus CFD computations of the partial admitted turbine stage. In the present study, a comprehensive analysis of the internal flow and aerodynamic loss mechanisms in a supersonic, axial single stage impulse 18.3 kW ORC turbine operating with an ethanol/water gas-mixture as working fluid at a partial admission ratio of 40 % based on steady-state CFD computations is presented. A comparison of numerical and experimental results for a partial admission ratio of 20 % and 40 % shows, that for a partial admission ratio of 40 % efficiency predictions based on steady-state simulations are within the measurement uncertainty. To extract and quantify the magnitude of the occurring loss mechanisms, the entropy generation rate is analysed. The results show an entropy generation between the rotor blades and the closed stator passages, which has a significant influence on the turbine performance and leads to a reduction of efficiency of about 2 to 4.5 ppt. This was found to be related to a strong jet induced in the narrow gaps between the rotor leading edges and the trailing edges of the closed stator passages, which mixes with the stagnant flow in the following nozzle sections.
Keywords
- axial turbine, losses, Organic Rankine Cycle, partial admission, real gas CFD, supersonic
ASJC Scopus subject areas
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ASME Turbo Expo 2022: Turbomachinery Technical Conference and Exposition : Turbomachinery - Axial Flow Turbine Aerodynamics; Deposition, Erosion, Fouling, and Icing; Radial Turbomachinery Aerodynamics. American Society of Mechanical Engineers(ASME), 2022. V10BT30A028 (Proceedings of the ASME Turbo Expo; Vol. 10B).
Research output: Chapter in book/report/conference proceeding › Conference contribution › Research › peer review
}
TY - GEN
T1 - Numerical Investigation of Loss Mechanisms in a Partially Loaded Supersonic ORC Axial Turbine Stage
AU - Ziaja, Karl
AU - Post, Pascal
AU - Schramm, Andreas
AU - Willers, Ole
AU - Seume, Joerg R.
AU - di Mare, Francesca
PY - 2022/10/28
Y1 - 2022/10/28
N2 - Industrial processes, small-scale power plants or internal combustion engines produce a high amount of waste heat as a by-product. The Organic Rankine Cycle (ORC) technology allows to recover that heat more efficiently compared to steam/water in conventional Clausius-Rankine cycles. For a comparably efficient and economical operation over a wide range of operating conditions, partial admission control appears to be a well-suited design option for ORC turbines. However, accurate numerical performance prediction of a partial admitted turbine stage is challenging and requires full annulus CFD computations of the partial admitted turbine stage. In the present study, a comprehensive analysis of the internal flow and aerodynamic loss mechanisms in a supersonic, axial single stage impulse 18.3 kW ORC turbine operating with an ethanol/water gas-mixture as working fluid at a partial admission ratio of 40 % based on steady-state CFD computations is presented. A comparison of numerical and experimental results for a partial admission ratio of 20 % and 40 % shows, that for a partial admission ratio of 40 % efficiency predictions based on steady-state simulations are within the measurement uncertainty. To extract and quantify the magnitude of the occurring loss mechanisms, the entropy generation rate is analysed. The results show an entropy generation between the rotor blades and the closed stator passages, which has a significant influence on the turbine performance and leads to a reduction of efficiency of about 2 to 4.5 ppt. This was found to be related to a strong jet induced in the narrow gaps between the rotor leading edges and the trailing edges of the closed stator passages, which mixes with the stagnant flow in the following nozzle sections.
AB - Industrial processes, small-scale power plants or internal combustion engines produce a high amount of waste heat as a by-product. The Organic Rankine Cycle (ORC) technology allows to recover that heat more efficiently compared to steam/water in conventional Clausius-Rankine cycles. For a comparably efficient and economical operation over a wide range of operating conditions, partial admission control appears to be a well-suited design option for ORC turbines. However, accurate numerical performance prediction of a partial admitted turbine stage is challenging and requires full annulus CFD computations of the partial admitted turbine stage. In the present study, a comprehensive analysis of the internal flow and aerodynamic loss mechanisms in a supersonic, axial single stage impulse 18.3 kW ORC turbine operating with an ethanol/water gas-mixture as working fluid at a partial admission ratio of 40 % based on steady-state CFD computations is presented. A comparison of numerical and experimental results for a partial admission ratio of 20 % and 40 % shows, that for a partial admission ratio of 40 % efficiency predictions based on steady-state simulations are within the measurement uncertainty. To extract and quantify the magnitude of the occurring loss mechanisms, the entropy generation rate is analysed. The results show an entropy generation between the rotor blades and the closed stator passages, which has a significant influence on the turbine performance and leads to a reduction of efficiency of about 2 to 4.5 ppt. This was found to be related to a strong jet induced in the narrow gaps between the rotor leading edges and the trailing edges of the closed stator passages, which mixes with the stagnant flow in the following nozzle sections.
KW - axial turbine
KW - losses
KW - Organic Rankine Cycle
KW - partial admission
KW - real gas CFD
KW - supersonic
UR - http://www.scopus.com/inward/record.url?scp=85141343415&partnerID=8YFLogxK
U2 - 10.1115/GT2022-82852
DO - 10.1115/GT2022-82852
M3 - Conference contribution
AN - SCOPUS:85141343415
T3 - Proceedings of the ASME Turbo Expo
BT - ASME Turbo Expo 2022: Turbomachinery Technical Conference and Exposition
PB - American Society of Mechanical Engineers(ASME)
T2 - ASME Turbo Expo 2022: Turbomachinery Technical Conference and Exposition, GT 2022
Y2 - 13 June 2022 through 17 June 2022
ER -