Nonlinear airfoil characteristics crossed with Betz theory. Corrections applied: Glauert, Prandtl, Spera.
Useful model aspects:
- Rotor can be connected with generator by modelica flange
- Rotor can have non axial direction to wind
- Blades are parametrized by files (section radius, chord, twist, thickness and airfoil characteristic file)
- Airfoil characteristics can be inteerpolated between given thicknessees
- Pitch angle is controlled all time, each blade can have independent pitch
- You can set many rotors in one WindSource, couple wind distributions or connect rotor WindSource with many rotors
- Gyroscopic torque is coupled to construction by frame.
Sample input files
Blade Geometry
"Radius [m]" "Chord [m]" "Twist [deg]" "Characteristic file [""]" "Thickness [%]"
2.70 1.090 15.0 "D:/OM_Turbine/RISO/NACA_63n-2nn_2D.txt" 24.6
3.55 1.005 09.5 "D:/OM_Turbine/RISO/NACA_63n-2nn_2D.txt" 20.7
4.40 0.925 06.1 "D:/OM_Turbine/RISO/NACA_63n-2nn_2D.txt" 18.7
5.25 0.845 03.9 "D:/OM_Turbine/RISO/NACA_63n-2nn_2D.txt" 17.6
6.10 0.765 02.4 "D:/OM_Turbine/RISO/NACA_63n-2nn_2D.txt" 16.6
6.95 0.685 01.5 "D:/OM_Turbine/RISO/NACA_63n-2nn_2D.txt" 15.6
7.80 0.605 00.9 "D:/OM_Turbine/RISO/NACA_63n-2nn_2D.txt" 14.6
8.65 0.525 00.4 "D:/OM_Turbine/RISO/NACA_63n-2nn_2D.txt" 13.6
9.50 0.445 00.0 "D:/OM_Turbine/RISO/NACA_63n-2nn_2D.txt" 12.6
Airfoil characteristics
#1
double lift(35,6) # thickness, alfa - lift
0.00 12.0 15.0 16.0 21.0 25.0 # foil thicknesses
-4.00 -0.25 -0.25 -0.25 -0.25 -0.25
-2.00 -0.06 -0.06 -0.06 -0.06 -0.06
0.00 0.16 0.16 0.16 0.16 0.16
2.00 0.38 0.38 0.38 0.38 0.38
4.00 0.60 0.60 0.60 0.60 0.60
6.00 0.82 0.82 0.82 0.82 0.81
8.00 1.04 1.03 1.01 1.00 0.98
10.0 1.26 1.23 1.19 1.14 1.08
12.0 1.43 1.36 1.29 1.20 1.12
14.0 1.50 1.42 1.32 1.21 1.12
16.0 1.34 1.30 1.25 1.18 1.09
18.0 0.80 1.05 1.10 1.12 1.06
20.0 0.70 0.85 1.00 1.05 1.04
25.0 0.92 0.95 0.97 0.99 1.01
30.0 0.99 1.00 1.01 1.02 1.03
40.0 0.99 1.00 1.01 1.02 1.03
50.0 0.92 0.92 0.92 0.92 0.92
#2
double drag(35,6) # thickness, alfa - lift
0.00 12.0 15.0 16.0 21.0 25.0 # foil thicknesses
-4.00 0.0080 0.0080 0.0080 0.0080 0.0080
-2.00 0.0060 0.0060 0.0060 0.0060 0.0060
0.00 0.0048 0.0052 0.0058 0.0064 0.0073
2.00 0.0048 0.0052 0.0058 0.0063 0.0072
4.00 0.0056 0.0058 0.0061 0.0065 0.0073
6.00 0.0080 0.0080 0.0080 0.0079 0.0078
8.00 0.0110 0.0110 0.0108 0.0105 0.0102
10.0 0.0158 0.0156 0.0154 0.0152 0.0150
12.0 0.0240 0.0230 0.0225 0.0218 0.0210
14.0 0.0400 0.0380 0.0360 0.0340 0.0320
16.0 0.0700 0.0700 0.0700 0.0700 0.0700
18.0 0.1500 0.1500 0.1500 0.1500 0.1500
20.0 0.2150 0.2200 0.2250 0.2300 0.2350
25.0 0.3700 0.3600 0.3500 0.3400 0.3300
30.0 0.4700 0.4700 0.4600 0.4500 0.4500
40.0 0.6600 0.6600 0.6600 0.6600 0.6600
50.0 0.8500 0.8500 0.8500 0.8500 0.8500
Validation based on final report
of IEA AnnexXVIII: ’Enhanced Field Rotor Aerodynamics Database’, Netherlands,
Energy research Centre of the Netherlands ECN, 2002.
Chosen turbines - RISO and NREL. Airfoil characteristics taken from the exprimental data provided in the report.
Designations:
-
$P$ - power -
$\alpha$ - angle of attack at section -
$\alpha_{in}$ - inflow angle of attack at section -
$\theta$ - blade tip pitch angle -
$\beta$ - tilt angle -
$\gamma$ - azimuthal angle -
$\alpha_H$ - Shear coefficient -
$v_w$ - wind speed at hub (measured at different points in report) -
$t$ - time
