Payam Sabaeifard - Ph.D. Student of Mechanical Engineering, Faculty of Mechanical and Energy Systems
Majid Jamil - Ph.D. of Mechanical Engineering, Department of Energy, Materials and Energy Research Center, Karaj, Tehran, Iran

The aim of this paper is to gain an insight into the unsteady flow field developing around a vertical axis wind turbine of Savonius type and present a method to predict its transient poweroutput. Due to its principle of operation and the sequential variation of blades angle, significant unsteady effects including separation and vortex are observed which can affect turbinesaerodynamic efficiency. In these conditions, the turbulence modeling by means of Realizable k-εpermits to gain reasonable results compared with experiments. The research covers both energy and exergy analysis of a model turbine with respect to the first and second laws of thermodynamics. The exergetic efficiency of rotor is studied for different operating conditions. Itis shown that the second law provides unique conception beyond a first law analysis, therewith providing an effective design tool for wind energy systems

Wind Energy, Savonius Wind Turbine, Exergy Analysis, Computational Fluid Dynamics