7th World Summit for Small Wind (WSSW2016) / Technology Development Development process of a vertical axis wind turbine Daniel Lehser-Pfeffermann Wind energy lab, htw saar Germany Day 2 18.03.2016 7th World Summit for Small Wind (WSSW2016), Husum 1
7th World Summit for Small Wind (WSSW2016) / Technology Development Overview Motivation and Objective Design code comparison, Reynolds number effects Definition and design of a scaled VAWT Wind tunnel experiments Conclusion and outlook 7th World Summit for Small Wind (WSSW2016), Husum 2
Motivation and Objective Why designing another VAWT? 7th World Summit for Small Wind (WSSW2016), Husum 3
Motivation and Objective Improving methods and tools for rotor-design understanding rotor aerodynamics development of control strategies blade manufacturing technologies 7th World Summit for Small Wind (WSSW2016), Husum 4
Urban measurement data - System Long time measurement (one year) Positioning of a measurement system on a tower (5 m over roof top) Building a frequency distribution of the wind speed over time 7th World Summit for Small Wind (WSSW2016), Husum 5
Working principle of VAWT Cyclic variation of Angle Of Attack (AOA), depends on freestream wind and turning speed: TSR aerodynamic forces (lift, drag tangential, normal forces) absolute freestream wind velocity absolute velocity blade rotational velocity AOA relative velocity blade 11.2.2015 Labor Windenergietechnik 2015 6
Working principle of VAWT Cyclic variation of Angle Of Attack (AOA), depends on freestream wind and turning speed: TSR aerodynamic forces (lift, drag tangential, normal forces) Design-calculation Aerodynamic models to compute forces based on (measured) lift and drag coefficients 11.2.2015 Labor Windenergietechnik 2015 7
Design code comparison Methods and tools Single (Templin, 1974) / Double Streamtube (DST) Multiple Streamtube (MST): DART (Strickland, 1975) VAWT_POWER, RE-number dependency of aerodynamic coeff. included (htwsaar, 2013) Double Multiple Streamtube (DMST): CARDAA/V/X (Paraschivoiu, Montréal, 1981) QBLADE (Wendler, Moesus, Marten, TU-Berlin, 2014) Vortex-Method VDART2, VDART3 (Strickland et al., 1980) CACTUS: Code for Axial and Cross-flow Turbine Simulation, 3D free-vortex code, lifting line approximation, RE (Murray, Barone, Sandia National Laboratories, 2011) CFD (ANSYS CFX, FLUENT) 7th World Summit for Small Wind (WSSW2016), Husum 8
Method: Multiple Streamtube (MST), verification Re=3.00E+06=const. (no RE number dependency), NACA0012, no virtual camber AOA Quelle James H. Strickland, Sand75-0431-report, The Darrieus Turbine: A performance prediction model using multiple streamtubes, 1975 7th World Summit for Small Wind (WSSW2016), Husum 9
Parameter Study (MST): H-ROTOR or DARRIEUS Parameter Study H/R = 2.25 Solidity DARRIEUS H-ROTOR S S 7th World Summit for Small Wind (WSSW2016), Husum 10
NACA 0018: Reynolds-number influences CL and CD are functions of the angle of the airfoil to the flow, their Reynolds- and Mach number. The lift coefficient CL refers to the dynamic lift characteristics of a two-dimensional foil section, with the airfoil reference area (chord and height) Sheidahl, Klimas: Aerodynamic Characteristics of Seven Symmetrical Airfoil Sections Through 180- Degree Angle of Attack for Use in Aerodynamic Analysis of Vertical Axis Wind Turbines, Sandia National Laboratories, SAND80-2114, 1981 7th World Summit for Small Wind (WSSW2016), Husum 11
Reynolds-number influences: MST vs. CACTUS H/R = 2.25 radius R = 1m chord l=0.13m Re=const. Re.ne. const. free wind velocity c0 (m/s) c0 7th World Summit for Small Wind (WSSW2016), Husum 12
VAWT, Labormodell, MS 1:2: Resultierende Blattlasten drive train 7th World Summit for Small Wind (WSSW2016), Husum 13
VAWT, Labormodell, MS 1:2: Resultierende Blattlasten MPa Example: Lift force(2150n) Isotrope material Thicknees 2mm, E=50000MPa, nue=0.3 MPa 7th World Summit for Small Wind (WSSW2016), Husum 14
Wind tunnel experiments 7th World Summit for Small Wind (WSSW2016), Husum 15
Scaled rotor, MST Design and building up a scaled prototype starting torque 7th World Summit for Small Wind (WSSW2016), Husum 16
Conclusion and outlook Long time measurement Design method study Rotor design Test on test bench Building up prototype FE-calculations Power coefficient test in high tip speed ratio Profit from experiences of the scaled prototype for a larger prototype Field test on university roof 7th World Summit for Small Wind (WSSW2016), Husum 17
Thank you for attention! Want more informations? Visit us here on exhibition stand 3C29! Contact details: Prof. Dr.-Ing. Tobias Müller Lab of wind energy technologies Daniel Lehser-Pfeffermann M.Sc. tobias.mueller@htwsaar.de Daniel.pfeffermann@htwsaar.de Lab of Wind Energy Technologies 18