Title
Effect of CO2-based binary mixtures on the performance of radial-inflow turbines for the supercritical CO2 cycles
Author
Yang, Yueming (Shandong University)
Wang, Xurong (Henan University of Urban Construction)
Hooman, K. (TU Delft Process and Energy) 
Han, Kuihua (Shandong University)
Xu, Jinliang (North China Electric Power University)
He, Suoying (Shandong University)
Qi, Jianhui (Shandong University; North China Electric Power University)
Department
Process and Energy
Date
2023
Abstract
Recently, the supercritical carbon dioxide (SCO2) power cycle has become a hotspot in the field of energy-efficient utilization. The utilization of additives in the power cycle has been proven to be an effective way to improve the SCO2 power cycle efficiency. As one of the core components of the system, the influence of CO2-based mixtures on turbine performance needs to be further explored. In this study, the preliminary design and three-dimensional numerical simulation of a 500 kW radial-inflow turbine (RIT) for small-scale SCO2 power systems were carried out. Furthermore, the design and off-design performance of high Reynolds number and small size turbine under the change of the CO2-based binary mixture compositions and mixing ratios were studied. Increasing the amount of nitrogen, oxygen, or helium into CO2 has a negative effect on the RIT performance, and the appropriate amount of xenon or krypton can improve the turbine efficiency. Moreover, mixtures with higher krypton additions adapt to higher heat source conditions. The loss of the turbine stage passage shows that a large amount of helium greatly reduces the working fluid density, and the high amount of xenon has a great influence on the dynamic viscosity, which all makes the RIT operation deviate from the steady state. Therefore, the CFD model simulation fails indicating that RIT designed based on pure CO2 may not run smoothly and continuously. The losses in the stage with pure CO2 and CO2–Kr mixture were investigated. The results indicate that the losses originated from the stator cannot be ignored and that the improvement of efficiency is mainly owed to the reduction in clearance losses. There is no doubt that the viewpoints proposed in this paper have significant reference value for the practical application of the SCO2 power cycle using mixtures.
Subject
CO-based binary mixture
Numerical simulation
Radial-inflow turbine
Supercritical carbon dioxide
Turbine stage losses
To reference this document use:
http://resolver.tudelft.nl/uuid:008210d5-61ec-4b11-8799-855609248ddc
DOI
https://doi.org/10.1016/j.energy.2022.126429
Embargo date
2023-06-19
ISSN
0360-5442
Source
Energy, 266
Bibliographical note
Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.
Part of collection
Institutional Repository
Document type
journal article
Rights
© 2023 Yueming Yang, Xurong Wang, K. Hooman, Kuihua Han, Jinliang Xu, Suoying He, Jianhui Qi