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

Year 2020, Volume: 2 Issue: 2, 78 - 91, 26.06.2020

Ekom Etuk R. S. Ebhojıaye Patrick Amiolemhen

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

References

• [1] Duque, E. P. N., Burklund, M. D. and Johnson, W. (2003). Navier-stoke and Comprehensive Analysis Performance Predictions of the Nrel Phase Vi Experiment. 22nd ASME Wind Energy Symposium, Reno, Nevada, USA, January, 2003. American Institute of Aeronautic and Astronauts, 2003-0355.
• [2] Bertagnolio, F., Sorensen, N. N. and Rasmussen, F. (2004). New Insight into the Flow arrond a Wind Turbine Airfoil Section. Special Topic Conference, The Science of making Torque from Wind, Delft, 19-21 Aril 2004, The Netherlands.
• [3] Alrobaian, A. A., Khan, S. A., Asadullah, M., Ahmed, F. and Imtiyaz, A. (2018). A New Approach to Low-cost Open-typed Subsonic Compressible Flow Wind Tunnel for Academic Purpose. International Journal of Mechanical and Production Engineering Research and Development, 8(6), 383-394.
• [4] Winslow, J., Otsuka, H., Govindarajan, B. and Chopra, I. (2018). Basic Understanding of Airfoil Characteristics at Low Reynolds Numbers (104-105). Journal of Aircraft, 55(3), 1050-1061.
• [5] Arun, A. K. and Surya, J. (2019). A Comparison of the Straight Blade and Swept Back Blade Horizontal Axis Wind Turbine. SSRG International Journal of Mechanical Engineering, 2348-8360, 30-35.
• [6] Mohokar, A. and Kale, N. W. (2017). Development of the Performance of Small Horizontal Axis Wind Turbine Blade by Optimizing its Chord Using QBlade Software. International Journal of Advanced Engineering and Research Development, 4(11), 790-796.
• [7] Gantasala, S., Tabatabaei, N., Cervantes, M. and Aidanpaa, J. (2019). Numerical Investigation of the Aeroelastic Behaviour of a Wind Turbine with Iced Blades. Energies, 12(2422), 1-24.
• [8] Etuk, E. M., Ikpe, A. E. and Adoh, U. A. (2020). Design and Analysis of Displacement Models For Modular Horizontal Wind Turbine Blade Structure. Nigerian Journal of Technology, 39(1), 121-130.
• [9] Schubel, P. J. and Crossley, R. J. (2012). Wind Turbine Blade Design. Energies, 5, 3425-3449.
• [10] Kandil, M. A. F. and Elnady, A. O. (2017). Performance of GOE-387 Airfoil Using CDF. International Journal of Aerospace Sciences, 5(1), 1-7.
• [11] Tang, H., Lei, Y., Li, X. and Fu, Y. (2019). Numerical Investigation of the Aerodynamic Characteristics and Attitude Stability of aBio-Inspired Corrugated Airfoil for MAV or UAV Applications. Energies, 12(4021), 1-25.