Investigation of low reynolds number air and water flow over double blade profile and aerodynamic performance analysis

As traditionally, in our country and in the world, standart turbine airfoils are used for generating energy. Provided that the maximum lift coefficient of the blade is around 1.6. By using these turbines, minimum required wind speed is between 6-7 m/s for generating energy. The purpose of this study, reveal that a wind turbine blade profile which can provide high performance and produce electric energy from hydrokinetic energy with use this profile. In this thesis, fluid changes of around the airfoil analysed in the free flow.In air an water conditions, numerical solutions derived with FLUENTTM program at different angles of attack, different Re numbers, different distances between the blades and different blade span ratio. NACA4412 blade profile?s numerical solutions were compared with this numerical solutions which examined under the same conditions. Fine mesh is used with 43969 cells in GAMBITTM program to obtain the most accurate and precise results. In different conditions, optimum blade form has reached with obtained pressure contours, pressure coefficient, distribution, maximum lift coefficient, maximum CL/CD ratio, velocity contours, stream lines, turbulence intensity contours and vorteks break frequency of blade profile. While reaching this solutions, the Realizable k-? model has been used, which is the most appropriate similarity turbulence model in FLUENTTM program. Obtained the optimum blade?s twist angle, which is changing with tip speed ratio, with used blade element momentum theory. In air flow, while the distance between the blades h/c1=0.95, blade span ratio c2/c1=0.73 and Re=1.5x105 number, the maximum lift coefficient as obtained 2.230 at 230 attack angle. But, CL/CD ratio is more important to provide maximum power coefficient and blade form is designed according to this ratio. The optimum attack angle was chosen 120. Because, the maximum CL/CD ratio was obtained at this attack angle while the distance between the blades h/c1=0.95, blade span ratio c2/c1=0.73 and Re=1.5x105 number. For NACA4412 blade profile, the maximum lift coefficient as obtained 1.1 at 160 attack angle. In water flow, while the distance between the blades h/c1=0.88, blade span ratio c2/c1=0.64 and Re=2.24x105 number, the maximum lift coefficient as obtained 2.4 at 300 attack angle. But, the optimum attack angle was chosen 180. Because, the maximum CL/CD ratio was obtained at this attack angle while the distance between the blades h/c1=0.95, blade span ratio c2/c1=0.73 and Re=4.5x105 number. For NACA4412 blade profile, the maximum lift coefficient as obtained 1.335 at 180 attack angle. As a result of calculations, double blade profile?s aerodynamic performance was found to be higher, which is used in air and water flows, according to NACA4412 blade profile.