FINAL PRESENTATION 2 - no name

17
An Empirical Study into the Power Dynamics of a Standard Wind Turbine Model Subject to Various Rotor-Blade Angle Tilt Offsets

Transcript of FINAL PRESENTATION 2 - no name

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An Empirical Study into the Power Dynamics of a

Standard Wind Turbine Model Subject to Various

Rotor-Blade Angle Tilt Offsets

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Introduction• Lift production is highest on the outer section of the wind turbine blade (Figure 1)

• Goal is to analyze the torque, rotational speed, efficiency, and power output of wind turbine with the turbine blades tilted over a range of offset angles. (Refer to Figure 2)

• We plan to create the following angular offset rotor parts (10 total) : 0°, 0° (2 blades for experimental control part) +4°, - 4°, +7°, - 7°, +10°, - 10°, +30°, - 30°.

- Tilt+ Tilt 0 Tilt

Figure 1: Lift Production vs. blade section Figure 2: Sample of Different Tilt Angles

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Turbine Blade Design and Analysis Tools

Design:

Analysis:

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Constant Variables in Blade Design

Constant Rotor

Swept AreaConstant Blade Pitch Angle

Blade Pitch

Angle ≈ 22.00°

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Vertical Reference Plane(0° rotational offset)

Approval For 3D Printing of Ten Blades

Example Blade: -7° Blade Rotational Offset From Vertical Reference Plane

Rotor Axis of Rotation(Rotor Hub, connects to generator-

nacel testing fixture)

-7° Rotational Rotor Blade Offset Angle -Please Note:

• We wish to 3D-print 10 rotor parts

total (made with two 16” x 14” 3D-

printer trays, approximately 10-15

hours of manufacturing time).

• Each rotor part will be 6 inches in

outer diameter.

• Parts will be made from polycarbonate

(for durability in wind tunnel).

• 10 rotor parts can fit on each 3D-

printer 16” x 14” tray.

• We plan to create the following

angular offset rotor parts (10 total) :

0° x 2 (experimental control part)

+4°, - 4°, +7°, - 7°, +10°, - 10°,

+30°, - 30°.

Quantitative Single Rotor-Part Reference

Metrics (from Solidworks):

1. Polycarb Density = 0.04 pounds per cubic inch

2. Total Mass = 0.01 lbm/ per rotor part

3. Total Volume = 0.26 in^3/ per rotor part

4. Total Surface area = 8.76 in^2 / per rotor part

5. $20.00 Printing Price per cubit inch.

10 rotor parts ≈ 2.6 cubic inches total ≈ $50

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3D Printing Process

• ≈ $ 50.00 to print 10 parts in polycarbonate material.

• 10-15 hour printing time (overnight).

Placement on 14’’X16’’ 3D printer

Tray

ASU’s Fortus 400MC 3D

Printer

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Physical Analysis Set-Up

Wind Turbine

Blades

IR Sensor to

measure angular

velocity

Electric

Generator

Electrical

Output to

Multi-Meter

Angular

Velocity Data

Output to

DAQ

IR Sensor Support

(Adjustable to multiple

blade angles)

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Wind Tunnel Testing Variations

(10 Rotors w/ Angles: 2x 0o, ±4o, ±7o, ±10o, ±30o) x

(4 Wind Speeds: 7 m/s, 10 m/s, 12 m/s, 17 m/s) x

(2 sets of tests: Open Circuit and Closed Circuit)

= 80 wind tunnel tests

Constants

Ambient Temperature and Pressure

Resistance

Rotor Swept Area

Results

Maximum Voltage Produced

Angular Velocity

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Open Circuit Testing Procedures1. Set rotor in place

2. Ramp up to maximum testing speed (17 m/s)

3. Record voltage and angular frequency graph at each

wind speed

4. Test through all 4 wind speeds

5. Repeat for the remaining 9 rotors

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Closed Circuit Testing Procedures1. Setup the resistor to create a closed circuit

2. Set rotor in place

3. Ramp up to maximum testing speed (17 m/s)

4. Record voltage and angular frequency graph at each

wind speed

5. Test through all 4 wind speeds

6. Repeat for the remaining 9 rotors

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Experimental DataConfiguration Power Flow Diagram

Blade

Efficiency &

Losses

Generator

Efficiency &

Losses

Air Velocity, Air

Density Data

Pair = ½*ρ*A*vair^3

Angular Velocity,

Voltage (OC) Data

Pblades = I * α * ω*(Based on Ang. Velocity Data)

Angular Velocity, Voltage

(OC) Data

Pelectrical = V^2/R*(Voltage prop. to Ang.

Velocity Data)

Pair PelectricalPblades

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Rotor Angular Velocity vs. Wind Speed

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Rotor Angular Velocity Power Functions:ω = A*(vair)^b

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Rotor Angular Velocity vs. Tilt Angle Design Curve

Bimodal Curve

(2 Maxima)!

Positive Angle

Maxima ≈ +20°

Negative Angle

Maxima ≈ -25°

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Wind Tunnel Simulation Clip

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What Did We Determine?

• The tilt angle seems to affect the rotor’s power output (i.e. rotational velocity) along a very

nonlinear, bimodal curve.

o It was visually verified that both the +30° & -30° rotors spun faster than the

baseline 0° rotor.

o Multiple rotors with small offset angles (i.e. +7° to -7°) spun slower than the

extreme angles, and a few rotors (i.e. +4°) resisted rotation all together.

• For maximum power output (i.e. rotational velocity) at a given wind speed and blade

pitch angle (i.e. 22°), one should use a tilt angle at either of the two maxima on the

bimodal design curve chart.

• Physical Reasoning for this Nonlinear Relationship?

• Investigation needs to continue, varying pitch angles and tilt angle together to

better define how the two angles interact and possibly create stall points.

• However, in terms of the conical shape that is formed at the rotor’s extreme

angles: one could speculate either cyclonic (rotating wake) or pressurization

effects (nozzle/diffuser) come into play!

• Possible Explanation: As power imparted by the air to the blades is incoming,

the air forces act over a longer “chord” distance and/or is pressurized leading to

better extraction efficiencies.

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QUESTIONS?