Title: Modelling of energy and exergy efficiencies of a horizontal axis wind turbine based on the blade element momentum theory at different yaw angles

Authors: Ali Khanjari; Esmail Mahmoodi; Ali Sarreshtehdari; Mahmood Chahartaghi

Addresses: Department of Mechanical Engineering, Shahrood University of Technology, P.O. Box 36199951, Shahrood, Iran ' Department of Mechanical Engineering of Biosystems, Shahrood University of Technology, P.O. Box 36199951, Shahrood, Iran ' Department of Mechanical Engineering, Shahrood University of Technology, P.O. Box 36199951, Shahrood, Iran ' Department of Mechanical Engineering, Shahrood University of Technology, P.O. Box 36199951, Shahrood, Iran

Abstract: In this study, energy and exergy analyses of a horizontal axis wind turbine are presented based on blade element momentum theory (BEM) under different yaw angles. Velocity, temperature, pressure and specific humidity are considered as metrological parameters. The wind flow is assumed steady, and exergy destruction are taken to account for wind blades. Results show that the BEM can predict he axial and tangential forces in different spans satisfactory. It is interesting to note that by increasing of yaw angle from 0° to 15° at wind speeds from 10 to 24 m/s, the energy and exergy efficiencies see a slight decrease in comparison with yaw angle of 0°. At wind speeds from 18 to 24 m/s, under yaw angle of 30°, by rising the wind speed, energy and exergy efficiencies increase due to reduction of the axial force on the wind turbine rotor.

Keywords: yaw angle; energy and exergy efficiencies; MEXICO wind turbine; BEM modelling.

DOI: 10.1504/IJEX.2018.096002

International Journal of Exergy, 2018 Vol.27 No.4, pp.437 - 459

Received: 08 Feb 2018
Accepted: 25 Jul 2018
Published online: 06 Nov 2018 *

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