*1 *2 *3 PIV Measurement of Field of the Wind Turbine with a med Diffuser Kazuhiko TOSHIMITSU *4, Koutarou NISHIKAWA and Yuji OHYA *4 Department of Mechanical Engineering, Matsue National Collage of Technology, 14-4 Nishiikuma-cho, Matsue-shi, Shimane, 690-8518 Japan The paper presents the instantaneous flow velocity measurements of a wind turbine with a brimmed diffuser by particle image velocimetry (PIV). The PIV is used to show the velocity vectors of the inner and downstream flow fields of the model at Reynolds number, 110 5 for turbine blades rotating (3700 rpm) and no turbine blades. Furthermore the flow fields between with and without the turbine blades are compared. If the turbine blades are rotating, the flow disturbances in a brimmed diffuser are suppressed. And there are two large vortices at downstream region of the diffuser. One vortex after acts as suck in wind to the diffuser and raise the inlet flow velocity. Another large unsteady vortex appears at downstream. Consequently the wind turbine with a brimmed diffuser can be operated stably while the turbine blades are rotating. Key Words : Wind Mill, Visualization, PIV, Velocity Distribution, med Diffuser 1. 2003 9 20 81 2005 6 15 *1690-8518 14-4. *2 *3816-8580 6-1 E-mail: kaz@matsue-ct.jp 2. 1
Optical Lenses CCD Camera Laser Sheet Wind Turbine with med Diffuser Pitot Tube PC Fig.1 Experimental facility. Transparent Diffuser Double Pulsed Nd:YAG Laser L1 Pulse Generator To A B C D 30 L2Q2 seed Laser Sheet 3. Tabel 1 Critical dimensions of the wind turbine. Diffuser Angle 12 degrees Diffuser Length L / D 1.25 h / D 0.5 Tip Clearance h t 3mm (ht/d=1.5%) Hub to Tip Ratio 0.2 Velocity U 0 8 m/s Rynolds Number (based on D) Re 1.0 10 5 D=200mmdiameter of diffuser at turbine blades Blades 100 306 L=250 700 Fig.2 Schematic of wind turbine with brimmed diffuser. Fig.4 Photograph of the turbine blades. Fig.3 Photograph of the wind turbine Table 2 Design and experimental conditions of the turbine blades. Design Cond. Exp. Cond. Peripheral Speed rt k Ratio U 0 5 4.8 Rotor Radius r t 200 mm 98 mm Rotational Speed 2000 rpm 3700 rpm 2
Table 3 Areas images, conditions and figures by PIV. Location of Turbine blades image areas with no A Fig.6 Fig.7 B Fig.9 Fig.10 C Fig.13 Fig.14 D Fig.11 Fig.12 Fig.6 Overlaid PIV image and analysis [A] (with turbine). D C B A Fig. 5 Schematic of the areas imaged by PIV. 6, 7 [] m/s Fig.7 Overlaid PIV image and analysis [A] (no turbine). u 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 WITH TURBINE BLADES NO TURBINE BLADES Fig.8 Comparison of absolute velocity distribution. 3
Fig.9 Overlaid PIV image and analysis [B] (with turbine). Fig.11 Overlaid PIV image and analysis [D] (with turbine). Fig.10 Overlaid PIV image and analysis [B] (no turbine). 4 Fig.12 Overlaid PIV image and analysis [D] (no turbine).
Vortex B Vortex A Blades Fig.15 Schematic of flow (with turbine). Vortex B Separation Fig.16 Schematic of flow (no turbine). Fig.13 Overlaid PIV image and analysis [C] (with turbine). 4. Fig.14 Overlaid PIV image and analysis [C] (no turbine). A B 2 A B A 15 P&P (1) Ohya, Y. et al., Development of High-Performance Wind Turbine with a med-diffuser, Journal of the Japan Society for Aeronautical and Space Sciences, Vol. 50 (2002-12), pp. 477-482. (2) Ohya, Y. et al., Development of High-Performance Wind Turbine with a med-diffuser-part 2-, Journal of the Japan Society for Aeronautical and Space Sciences, Vol. 52 (2004-5), pp. 210-213. 5