Numerical parametric study of a Kaplan turbine incorporated with a sub runner considering analysis of hydraulic dissipation
In this paper, a novel approach on Kaplan turbines, proposed and published in a US patent, has been investigated numerically using CFD tool. This approach includes the incorporation of an extra runner, called sub runner, into the main runner of a typical Kaplan turbine. The sub runner, consisting of...
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| Language: | English |
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Elsevier
2025-03-01
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| Series: | Results in Engineering |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S2590123025002191 |
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| author | Amirhossein Khoddami Mojtaba Tahani Fathollah Pourfayaz Alireza Riasi Khalil Allah Sajadian |
| author_facet | Amirhossein Khoddami Mojtaba Tahani Fathollah Pourfayaz Alireza Riasi Khalil Allah Sajadian |
| author_sort | Amirhossein Khoddami |
| collection | DOAJ |
| description | In this paper, a novel approach on Kaplan turbines, proposed and published in a US patent, has been investigated numerically using CFD tool. This approach includes the incorporation of an extra runner, called sub runner, into the main runner of a typical Kaplan turbine. The sub runner, consisting of some blades, performs the task of passive control of the main runner blades' adjustment angle through a control mechanism, attached to the sub runner shaft and its blades, in case of altered operating condition. As a result of this, the main runner can operate at its optimum and maximum hydraulic efficiency at the changed operating condition. For this purpose, it is aimed to extract its underlying passive control logic through investigating the hydrodynamic behavior and flow characteristics within the overall turbine domain numerically, so that the safe and allowable region of the turbine operation is determined. The analysis has been carried out by considering two varying operating parameters i.e., sub runner angular velocity and blades adjustment angle at different on-cam flow rates. It was revealed that placing the sub runner at the bottom of the main runner will not be a practical solution at high angular velocities at low on-cam flow rates. This is due to the development of some unstable and transient flows between the two runners at these velocities, disrupting the sub runner energy extraction performance. Furthermore, overall hydraulic efficiency improvements of 41.7, 24.8, and 18.4 percent could be achieved under the designed adjustment angle of the blades at first, second, and third on-cam flow rates, respectively, by adding the sub runner to the main turbine. Therefore, more design considerations should be made in the minimization of the associated hydraulic losses. |
| format | Article |
| id | doaj-art-0177730d22584b7092367b3da0b0cef4 |
| institution | Kabale University |
| issn | 2590-1230 |
| language | English |
| publishDate | 2025-03-01 |
| publisher | Elsevier |
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| series | Results in Engineering |
| spelling | doaj-art-0177730d22584b7092367b3da0b0cef42025-01-28T04:14:51ZengElsevierResults in Engineering2590-12302025-03-0125104131Numerical parametric study of a Kaplan turbine incorporated with a sub runner considering analysis of hydraulic dissipationAmirhossein Khoddami0Mojtaba Tahani1Fathollah Pourfayaz2Alireza Riasi3Khalil Allah Sajadian4College of Interdisciplinary Science and Technology, University of Tehran, Tehran, IranCollege of Interdisciplinary Science and Technology, University of Tehran, Tehran, Iran; Corresponding authors.College of Interdisciplinary Science and Technology, University of Tehran, Tehran, Iran; Corresponding authors.Marine and Hydrokinetic Energy Laboratory, School of Mechanical Engineering, College of Engineering, University of Tehran, Tehran, 11155-4563, IranMarine and Hydrokinetic Energy Laboratory, School of Mechanical Engineering, College of Engineering, University of Tehran, Tehran, 11155-4563, IranIn this paper, a novel approach on Kaplan turbines, proposed and published in a US patent, has been investigated numerically using CFD tool. This approach includes the incorporation of an extra runner, called sub runner, into the main runner of a typical Kaplan turbine. The sub runner, consisting of some blades, performs the task of passive control of the main runner blades' adjustment angle through a control mechanism, attached to the sub runner shaft and its blades, in case of altered operating condition. As a result of this, the main runner can operate at its optimum and maximum hydraulic efficiency at the changed operating condition. For this purpose, it is aimed to extract its underlying passive control logic through investigating the hydrodynamic behavior and flow characteristics within the overall turbine domain numerically, so that the safe and allowable region of the turbine operation is determined. The analysis has been carried out by considering two varying operating parameters i.e., sub runner angular velocity and blades adjustment angle at different on-cam flow rates. It was revealed that placing the sub runner at the bottom of the main runner will not be a practical solution at high angular velocities at low on-cam flow rates. This is due to the development of some unstable and transient flows between the two runners at these velocities, disrupting the sub runner energy extraction performance. Furthermore, overall hydraulic efficiency improvements of 41.7, 24.8, and 18.4 percent could be achieved under the designed adjustment angle of the blades at first, second, and third on-cam flow rates, respectively, by adding the sub runner to the main turbine. Therefore, more design considerations should be made in the minimization of the associated hydraulic losses.http://www.sciencedirect.com/science/article/pii/S2590123025002191Kaplan turbinesPassive controlOn-cam flow ratesMaximum hydraulic efficiency |
| spellingShingle | Amirhossein Khoddami Mojtaba Tahani Fathollah Pourfayaz Alireza Riasi Khalil Allah Sajadian Numerical parametric study of a Kaplan turbine incorporated with a sub runner considering analysis of hydraulic dissipation Results in Engineering Kaplan turbines Passive control On-cam flow rates Maximum hydraulic efficiency |
| title | Numerical parametric study of a Kaplan turbine incorporated with a sub runner considering analysis of hydraulic dissipation |
| title_full | Numerical parametric study of a Kaplan turbine incorporated with a sub runner considering analysis of hydraulic dissipation |
| title_fullStr | Numerical parametric study of a Kaplan turbine incorporated with a sub runner considering analysis of hydraulic dissipation |
| title_full_unstemmed | Numerical parametric study of a Kaplan turbine incorporated with a sub runner considering analysis of hydraulic dissipation |
| title_short | Numerical parametric study of a Kaplan turbine incorporated with a sub runner considering analysis of hydraulic dissipation |
| title_sort | numerical parametric study of a kaplan turbine incorporated with a sub runner considering analysis of hydraulic dissipation |
| topic | Kaplan turbines Passive control On-cam flow rates Maximum hydraulic efficiency |
| url | http://www.sciencedirect.com/science/article/pii/S2590123025002191 |
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