Effects of Tip Injection and Mie Vanes on the Performance of a Model Wind Turbine Rotor

Transcription

1 Effects of Tip Injection and Mie Vanes on the Performance of a Model Wind Turbine Rotor A. Abdulrahim, E. Anık, O. Uzol Department of Aerospace Engineering METU Center for Wind Energy (METUWIND) Ankara, Turkey NAWEA 2015 Symposium, NORTH AMERICAN WIND ENERGY ACADEMY, June 9-11, 2015, Blacksburg, Virginia USA

2 OUTLINE Introduction The Tip Vortex Previous Studies Objective Experimental Setup Results Load measurements Wake measurements Conclusions Acknowledgments NAWEA 2015 Symposium, NORTH AMERICAN WIND ENERGY ACADEMY, June 9-11, 2015, Blacksburg, Virginia USA 2/17

3 Introduction The Tip Vortex Due to the lift generated by a wing/blade Aerodynamic performance losses Dominates the wakes, interacts with downstream rotors Noise Wind turbines, fixed-wing aircraft, rotorcraft, turbomachinery NAWEA 2015 Symposium, NORTH AMERICAN WIND ENERGY ACADEMY, June 9-11, 2015, Blacksburg, Virginia USA 3/17

4 Introduction Previous Studies on Tip Flow Control in Wind Turbines Tip Flow Control Techniques: Special type V-shaped winglets (Mie Vanes) (Shimizu et al. [2003]) Winglets (Johansen and Sorensen [2006]) Vortex diffusers (Bai et al. [2011]) Tip injection (Anik et al. [2014]), ( [2015]) Anik, E., Abdulrahim, A., Ostovan, Y., Mercan, B., Uzol, O., Active Control of the Tip Vortex: An Experimental Investigation on the Performance Characteristics of a Model Turbine. The Science of Making Torque from Wind (TORQUE2014), Journal of Physics: Conference Series 524 (2014) NAWEA 2015 Symposium, NORTH AMERICAN WIND ENERGY ACADEMY, June 9-11, 2015, Blacksburg, Virginia USA 4/17

5 Tip Injection Research in Wind Turbines Objective To investigate the effects of tip injection and Mie Vanes on load and wake flow field characteristics NAWEA 2015 Symposium, NORTH AMERICAN WIND ENERGY ACADEMY, June 9-11, 2015, Blacksburg, Virginia USA 5/17

6 Experimental Setup Open-jet wind tunnel 45 kw electric motor and 1.2 m diameter fan 4.30 m long circular diffuser with a 3 deg diffusion angle Two screens and a honeycomb 1.7 m jet exit diameter Maximum jet exit velocity 10 m/s. Turbulence intensity around 2.5% Jet Exit D exit = 1.7m Flow straighteners 2 Screens + 1 Honeycomb Diffuser L diffuser = 4.30 m Angle = 3 deg. 45 kw axial fan D fan = 1.25 m 3 straight sections L total = 1.40 m NAWEA 2015 Symposium, NORTH AMERICAN WIND ENERGY ACADEMY, June 9-11, 2015, Blacksburg, Virginia USA 6/17

7 Experimental Setup Blades with NREL S826 profile (Replica of the NTNU rotor used in the Blind Test Experiments, Adaramola and Krogstad [2011]) Rotor diameter 0.95 m. Non-linear twist and chord distributions 3D printed titanium blades 1.5 kw speed controlled AC servo motor T20WN/5Nm torque transducer 6- axes F/T transducer Pressure chamber, hollow shaft and pressurized hub for air transfer for tip injection from the rotor blades. NAWEA 2015 Symposium, NORTH AMERICAN WIND ENERGY ACADEMY, June 9-11, 2015, Blacksburg, Virginia USA 7/17

8 Experimental Setup NAWEA 2015 Symposium, NORTH AMERICAN WIND ENERGY ACADEMY, June 9-11, 2015, Blacksburg, Virginia USA 8/17

9 t Experimental Setup 0.8c c Shimizu, Y., Imamura, H., Matsumura, S., Maeda, T., 1995, Power Augmentation of a Horizontal Axis Wind Turbine Using a Mie-Type Tip Vane: Velocity Distribution Around the Tip of a HAWT Blade With and Without a Mie-Type Tip Vane, ASME Journal Solar Energy Engineering, Vol.117, pp NAWEA 2015 Symposium, NORTH AMERICAN WIND ENERGY ACADEMY, June 9-11, 2015, Blacksburg, Virginia USA 9/17

10 Results Load Measurements Measured power and thrust coefficient variations with TSR at U =5 m/s wind speed, for baseline, Mievane, injection momentum ratio of R M =0.2% (injection 100 l/min) and injection momentum ratio of R M =0.7% (injection 140 l/min) cases NAWEA 2015 Symposium, NORTH AMERICAN WIND ENERGY ACADEMY, June 9-11, 2015, Blacksburg, Virginia USA 10/17

11 Results Wake Flow Field Measurements Single sensor CTA Axial location of 0.5D downstream Step size of Δy=Δz=2.5 cm Traverse area of 65 cm x 65 cm NI DAQ system through a LabView program. Sampling rate of 5 khz for 5 seconds NAWEA 2015 Symposium, NORTH AMERICAN WIND ENERGY ACADEMY, June 9-11, 2015, Blacksburg, Virginia USA 11/17

12 Results Wake Flow Field Measurements-0.5D Velocity Baseline Mie Vane Tip injection Abdulrahim, A., Anik, E., B., Uzol, O., Effects of Mie Vanes and Tip Injection on the Performance and Wake Characteristics of a HAWT. AIAA SciTech, 4-8 January, San Diego, California NAWEA 2015 Symposium, NORTH AMERICAN WIND ENERGY ACADEMY, June 9-11, 2015, Blacksburg, Virginia USA 12/17

13 Results Wake Flow Field Measurements-0.5D Turbulence Intensity Baseline Mie Vane Tip injection Abdulrahim, A., Anik, E., B., Uzol, O., Effects of Mie Vanes and Tip Injection on the Performance and Wake Characteristics of a HAWT. AIAA SciTech, 4-8 January, San Diego, California NAWEA 2015 Symposium, NORTH AMERICAN WIND ENERGY ACADEMY, June 9-11, 2015, Blacksburg, Virginia USA 13/17

14 Results Wake Flow Field Measurements-0.5D Radial Variations Radial direction at 0.5D downstream. NAWEA 2015 Symposium, NORTH AMERICAN WIND ENERGY ACADEMY, June 9-11, 2015, Blacksburg, Virginia USA 14/17

15 Results Wake Flow Field Measurements-0.5D Radial Variations s s Velocity (left) and turbulence intensity (right) variations along the radial direction at 0.5D downstream. s is the distance along the data extraction line shown in the previous figure. NAWEA 2015 Symposium, NORTH AMERICAN WIND ENERGY ACADEMY, June 9-11, 2015, Blacksburg, Virginia USA 15/17

16 Conclusions Tip injection and Mie Vanes do influence wake flow field and load characteristics. Power and thrust coefficients are increased at high TSR values. Tip vortex region gets widened and pushed radially outward. Velocity levels and gradients around tip vortex region get reduced for both. Turbulence levels are increased in tip vortex region for injection while Mie Vanes causes decrease in TI levels. Flow field needs further investigation (more load data at different wind speeds and injection cases and more wake data) NAWEA 2015 Symposium, NORTH AMERICAN WIND ENERGY ACADEMY, June 9-11, 2015, Blacksburg, Virginia USA 16/17

17 Acknowledgments: This study is sponsored by: The Scientific and Technological Research Council of Turkey (TÜBİTAK) under the Grant No 112M105 METU Center for Wind Energy (METUWIND) Their support is greatly appreciated. NAWEA 2015 Symposium, NORTH AMERICAN WIND ENERGY ACADEMY, June 9-11, 2015, Blacksburg, Virginia USA 17/17