This paper opens up a new perspective on the aerodynamic performance of a wind turbine airfoil. More specifically, the paper deals with a steady, incompressible two-phase flow, consisting of air and two different concentrations of sand particles, over an airfoil from the National Renewable Energy Laboratory, NREL S809. The numerical simulations were performed on turbulence models for aerodynamic operations using commercial computational fluid dynamics (CFD) code. The computational results obtained for the aerodynamic performance of an S809 airfoil at various angles of attack operating at Reynolds numbers of Re = 1 × 10 6 and Re = 2 × 10 6 in a dry, dusty environment were compared with existing experimental data on air flow over an S809 airfoil from reliable sources. Notably, a structured mesh consisting of 80,000 cells had already been identified as the most appropriate for numerical simulations. Finally, it was concluded that sand concentration significantly affected the aerodynamic performance of the airfoil; there was an increase in the values of the predicted drag coefficients, as well as a decrease in the values of the predicted lift coefficients caused by increasing concentrations of sand particles. The region around the airfoil was studied by using contours of static pressure and discrete phase model (DPM) concentration.

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The current study deals with numerical simulations of a National Advisory Committee of Aeronautics (NACA) airfoil, NACA 0012, using a commercial Computational Fluid Dynamics (CFD) Code, in air phase flow as well as in two-phase flow of air and sand particles, which consisted of 1 percent and 5 percent sand particles in air. The simulations where accomplished for Reynolds number of Re=1.76×10 6 , at various angles of attack, on Realizable k-ε turbulence model and the injection of the particles was succeeded using the Discrete Phase Model (DPM). The validation of the obtained numerical results was achieved by comparing them with reliable experimental data from other researchers and it was shown that the existence of sand particles in the air influences the aerodynamic performance of the airfoil. In particular, the predicted lift coefficient was decreased and at the same time the drag coefficient was increased. By the help of contours of static pressure and DPM concentration, it was possible to study the region around NACA 0012 airfoil.

This paper concentrates on a new configuration for a wind turbine, named KIONAS. The main purpose is to determine the performance and aerodynamic behavior of KIONAS, which is a vertical axis wind turbine with a stator over the rotor and a special feature in that it can consist of several stages. Notably, the stator is shaped in such a way that it increases the velocity of the air impacting the rotor blades. Moreover, each stage's performance can be increased with the increase of the total number of stages. The effects of wind velocity, the various numbers of inclined rotor blades, the rotor diameter, the stator's shape and the number of stages on the performance of KIONAS were studied. A FORTRAN code was developed in order to predict the power in several cases by solving the equations of continuity and momentum. Subsequently, further knowledge on the flow field was obtained by using a commercial Computational Fluid Dynamics code. Based on the results, it can be concluded that higher wind velocities and a greater number of blades produce more power. Furthermore, higher performance was found for a stator with curved guide vanes and for a KIONAS configuration with more stages.

The main purpose of this study is to develop an understanding of the aerodynamic performance of a horizontal axis wind turbine (HAWT) operating in a dusty environment, with various concentration of dust in the flow domain. The computational analysis was accomplished by the commercial computational fluid dynamics (CFD) code ANSYS Fluent 16.0. Initially, a user-friendly developed application was utilized for the optimum blade geometry special characteristics calculation. The design of the HAWT rotor and meshing of the computational domain follows. The moving reference frame (MRF) model was applied for the rotary motion of the blades, the dust was added in the computational domain by the discrete phase model (DPM) and SST k–ω turbulence model was enabled. The power output of the studied HAWT, operating in several dusty environments, was estimated and compared with the power output of a particular HAWT in clean air. The flow field around the HAWT rotor, including the contours of pressure, particles dissipation rate and erosion rate on both blade sides, are shown. In general, it is concluded that the operation of a HAWT in a dusty environment results in degraded performance, due to the particles deposition on the blades.