POLAR SIMULATION OF SUBSONIC FLOW AROUND NACA 4610 AIRFOIL IN HORIZONTAL AXIS WIND TURBINE

Abstract

This study provide details on the characteristics of horizontal axis wind turbine airfoil under subsonic flow regime at distinct angle of attacks (AoA) using XFOIL. Using a fixed Mack number (Ma) of 1000,000 and Renolds number (Re), the XFOIL modelled cambered airfoil was simulated at various AoA including -10o, -5o, 0.0o, 5o, 10o, 15o, 22o and 25o to observe the variations in lift, drag, lift and drag coefficient and their effects on the overall wind turbine performance. It was observed that constant increase in AoA can prevent separation in airflow while continuous reduction in AoA can make airflow separation more pronounce, thereby, causing decrese in the rate at which the lift coefficient increases. A negative pitching moment coefficient was observed, indicating a nose-down moment which would reduce the angle of attack on the rotor blade. It was also found that the drag coefficient CD varied proportionately with the AoA, and lower CD values indicate less drag foces on the on the airfoil. The results indicated that the lift to drag ratio initially increase as the AoA increases upto a maximum point of 108.64, but as the AoA is increased further, the L/D ratio decreases until the stalling angle is reached. In summary, the rotor blade blade undergoes minimum drag at fairly low AoA while the lifting ability of the rotor is quite low at low AoA.

Keywords

• Wind turbine,Blade foil,Drag force,Aerodynamics,Lift force,Renolds number

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