| Popis: |
Startup capacity is always a concern to low wind speed turbines, especially the vertical axis wind turbine (VAWT). Efforts at developing low wind speed models still persist. Hence, the focus of this study is on the development of a new airfoil for VAWT, with better startup capacity, low tip loss, and devoid of dynamic stall, from the synergistic properties of four standard airfoils. The standard airfoils are DU06-W-200-dt, NACA0012h-sa, S822, and S823. The coordinates of these airfoils were employed to generate eleven new airfoils via the interpolation of the coordinate points. The airfoils were then analysed using QBlade v0.963 64bit, to determine the coefficients of lift (CL), drag (CD), pitching moment, and minimum pressure for various angles of attack, at a specific flow characteristics such as Reynold's number, density, kinematic viscosity, and Mach number. The Reynold's and Mach numbers were modified over a range of values to generate polar of airfoil performance for every wind speed. Variations of glide ratio, CL, and CD with angle of attack at constant Reynolds number were employed to determine the optimum airfoil. High aspect ratio was used to minimise the effect of tip loss. The outcome showed that the developed airfoil exhibits better performance, good startup capacity, with potential to generate up to 1, 11 and 13 kW at speeds of 2, 11 and 16 m/s, respectively. Flow, and pressure analysis show that the turbine with the blade airfoil will not experience dynamic stall as a result of pressure differences, irrespective of the azimuth. |
