Performance evaluation of a downwind diffuser on vertical axis wind turbine

Wang, Xiao Hang and Wong, Kok Hoe and Chong, Wen Tong and Ng, Jo Han and Qiu, Cheng Jun and Khor, Chong Shen (2022) Performance evaluation of a downwind diffuser on vertical axis wind turbine. International Journal of Energy Research, 46 (1, SI). pp. 351-369. ISSN 0363-907X, DOI

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Research has proven that the performance of a horizontal axis wind turbine (HAWTs) can be increased significantly by the application of a diffuser. It serves as a power augmented feature to draw higher wind flow toward the HAWT. However, research on integrating a diffuser onto vertical axis wind turbines (VAWTs) is scant, where most of the available power augmentation devices used for VAWTs are the convergent duct, deflector plate, shroud, and guide vanes which are placed in a proper configuration at the upwind. In this paper, laboratory tests and computational simulations have been carried out to study the impacts of a downwind diffuser on the performance of a VAWT. The diffuser is designed with the absence of a concentrator or flange and is placed downwind of the VAWT. Parametric computational fluid dynamics (CFD) studies were carried out for the downwind diffuser length and semi-opening angle. A five-bladed H-rotor was selected as the testing wind turbine, whereas the diffuser used was made up of flat plates. Both simulations and experiment results are consistent. From the experiments, it was found that a downwind diffuser increases the VAWT performance remarkably. The diffuser-augmented VAWT produced an increment in the maximum coefficient of power of 31.42% at the TSR 0.65 to 0.75. Moreover, the diffuser induced a better self-start ability on the VAWT. The simulation showed that the flow field at the diffuser promotes a flow expansion which created a lower-pressure region at downstream that accelerates the wind toward the VAWT, hence increasing the turbine performance significantly.

Item Type: Article
Funders: Ministry of Education, Malaysia [Grant No: FRGS/1/2020/TK0/USMC/02/3], Universiti Malaya [Grant No: IIRG011B-2019], University of Southampton Malaysia [Grant No: 590111115]
Uncontrolled Keywords: CFD simulation; Coefficient of power; Diffuser; Experiment; Vertical axis wind turbine
Subjects: T Technology > T Technology (General)
T Technology > TK Electrical engineering. Electronics Nuclear engineering
Divisions: Faculty of Engineering > Department of Mechanical Engineering
Depositing User: Ms. Juhaida Abd Rahim
Date Deposited: 25 Apr 2022 03:12
Last Modified: 25 Apr 2022 03:12

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