Wind Turbine
San Jose State University, Charles W. Davidson College of Engineering
E10 Introduction to Engineering
By Justin DeCastro, Cari Geldreich, Hugo Quiroz, and Ashley Mishra
March 24, 2011
Professor Athanasiou
Section 6

Project Summary The project that was assigned in lab was the wind turbine lab. The objective of this lab was to develop and construct a wind turbine that would create enough energy to conduct electricity. The goal of the assignment was to construct the most creative and stable structure so that it would withstand high winds. After constructing the turbine, which was 17 inches high and weight 255 grams, the next task was to test its stiffness using various amounts of weights and to look for the displacement. The maximum amount of displacement by the turbine was 4.81 mm. After finding out how stiff the turbine was, the next task was to measure the amount of power the turbine generated. The turbine worked quite well except for the fact that the blade broke within the first few minutes. The blade speed started out with 9703 RPM and went down to as low as 6000RPM when it had 6 light bulbs on. The turbine successfully completed all the objectives with ease. The only thing that it could’ve done better in was the stiffness test because it displaced more weight than it needed to.

Table of Contents
Introduction pg. 4
Turbine Structure Design Structure & Blade Design pg. 5 Structure & Blade Construction pg. 6 Power & Stiffness Tests pg. 7-9 Results pg. 10
Conclusion pg. 11
References pg. 12
Appendix A pg. 13
Appendix B pg. 14-15

Introduction
As the centuries have gone by, the need for renewable energy has grown. An excellent example of one of the newest renewable energies is the solar cell, which is put on houses and buildings to generate power and save money on power bills. Another type of renewable energy source is the wind turbine. The idea of wind turbines has been around since 1000 B.C., where people knew about dragging. Dragging is when the blades spin and generate power. Between 1850 and 1970 many of these turbines started making an appearance in valleys. The first wind turbine that was actually used for electricity purposes was made in Ohio by a man named Charles F. Brush. These turbines had an extra blade type thing that would brush the ground as seen in Figure 1. At that time, wind turbines had many blades and they were all connected. As the years went by, M.L. Jacobs had the idea to use the propeller of an airplane as a blade for a turbine. This is how the typical three blade turbine came into play. In the years 1973 to 1986, the wind turbine became more widely used and they started to be seen in large groups in places that had empty land as seen in Figure 2. In the 21st century, wind turbines are widely used not only in California, but also overseas in places like China, Dubai, and Europe. As this is a job for engineers, the task that needed to be fulfilled was making a turbine as good as the real life ones.
Details of the Wind Turbine Tower 1. Designs: a. Structure design:
There were several prototypes discussed for the structure of the turbine. Some of the ideas discussed were used soda cans, plastic gallon bottles, discarded pieces of PVC plumbing pipe, Legos, and old hangers. It was decided that the easiest material to construct the structure would be out of PVC pipe and wood.
PVC pipe was light and sturdy and could be easily manipulated when heated. Several prototypes were made using the PVC pipe but in conclusion we ended up designing and arch support with two supporting wood dowels for further stability.
Other prototypes were attempted such as a Styrofoam structure which was extremely light but was not stable enough. Another prototype was constructed out of wood in a tripod structure, the tower was light but also unstable. In the end we used the PVC pipe design because of its originality.

b. Blade design:
The blade design was chosen taking into account efficiency and cost. Four blades was an adequate decision the cost of having four blades instead of three was minimal and the efficiency calculated was much greater than a three blade design. The angle of attack for the blade design was about 18. 2. Construction: a. Structure
The construction of the structure took place outside the lab because it required power tools unavailable in the lab. The first task was to attach the PVC pipe to the bottom board, the PVC pipe was a half inch pipe, so we used a half inch drill. The pipe was glued in using epoxy and left to dry while a wooden support was made to hold the top board at the appropriate height of 17 inches from the bottom to the top. The PVC pipe was then heated up until it was wobbly and maneuverable and it was bent in the shape of an arch to fit right under the top board. After cooling down the PVC pipe was stiff and the top board was attached to the PVC pipe with a screw. Then the wooden dowels were fit and cut at an angle to support the top board. The structure was then painted and decorated beautifully.

b. Blade
The blade was constructed by a teacher assistant using a machine in lab; the material was some kind of very light but very brittle fiber 3. Tests a. Stiffness test
The structure’s stiffness was tested by adding weights on a string attached to the top of our tower. A device measuring displacement was placed at the front of the structure and the mass was increased to attain several values of load and displacement. Table 1 shows a graph of displacement and load.
Table 1. Displacement vs. Load Displacement (mm) | Load (N) | 0 | 0.196 | 0 | 0.49 | 0.16 | 0.98 | 0.48 | 1.96 | 2 | 4.9 | 4.13 | 9.8 | 4.81 | 11.76 |
Chart 1. Stiffness Chart

b. Electrical test
The efficiency of the blade design was tested by using a blower to blow 25 mph wind at the turbine making the blade rotate and create power. The turbine was connected to a power meter that displayed the instantaneous voltage, current, and power at certain loads. The power meter was also connected to a load box; the load box consisted of six light bulbs each adding more load as they are turned on. The speed of the blade in RPM was also recorded using a tachometer. Table 2 shows the data collected from the turbine blade test

Table 2. Power Measurement Current Amps (I) | Power Watts (W) | Blade Speed (RPM) | Voltage (V) | 0.02 | 0.04 | 9,703 | 6.8 | 0.19 | 1.23 | 9,088 | 6.09 | 0.38 | 2.15 | 8,438 | 5.5 | 0.55 | 2.84 | 7,783 | 5 | 0.69 | 3.1 | 7,320 | 4.46 | 0.84 | 3.44 | 6,747 | 4.11 | 0.95 | 3.3 | 6,209 | 3.54 |

Chart. 2 Voltage & Current

Chart 3. Current & Power Measurement

4. Results a. Stiffness
In the displacement vs. load graph the slope was calculated to be 2.4283. b. Electrical
In the electrical test the maximum power output was recorded at 3.44 W, with a load of 5 light bulbs, current of .84 Amps, voltage of 4.11 V, and speed of 6,747 RPM.

Conclusion By the end of the lab, we’ve created our wind turbine with the following characteristics * Height: 17 1/16 inches * Weight: 255 grams * Used birch wood material and a bent PVC pipe * Used a 4 blade design

The turbine successfully went through several tests with the following results: * Deflection coefficient = 2.483 * Maximum RPM = 9,703 * Maximum power generated = 3.44 watts
Improvements:
* Strengthen the tower with denser material for a greater deflection * Use a 5 blade design for the wind turbine

References
Angle of attack. (2011, March 20). Retrieved from http://en.wikipedia.org/wiki/Angle_of_attack

Dodge, D. (2006). 20th century developments.
Retrieved from http://telosnet.com/wind/

Hsu, P., Athanasiou, J., Anagnos, T., & Youssefi, K. (2011, March 23). E10 introduction to engineering. Retrieved from http://www.engr.sjsu.edu/e10/

Appendix A

Appendix B i. For our project we divided the task into two groups the first group, which consisted of Cari Geldreich and Justin DeCastro, was responsible for the structure design and manufacturing. The second group which consisted of, Ashley Mishra and Hugo Quiroz, was responsible for the blade design.

ii. For our project report we divided up into sections the divisions are as follows: * Cari Geldreich was responsible for the Turbine Blade Design Description and Performance section. * Justin DeCastro was responsible for the Introduction and Conclusion sections. * Ashley Mishra was responsible for the Table of Contents and Summary sections. * Hugo Quiroz was responsible for the References and Appendices sections and master editor. iii. One challenge we faced which was probably the biggest challenge, was designing the turbine blade. We were completely lost and no one in our group had good previous experience with Inventor. We resolved this problem by asking one of the groups around us to help us, we ended up creating a very efficient blade. What we learned was that communication is a very important skill to develop. Even though we were essentially competing to create a blade more efficient than all the other groups, the other group was still willing to help us.

iv. Teamwork Skill | Performance Level | 1) open and honest communication among members | 4 | 2) each individual carried his/her own weight | 4 | 3) collaboration in decision making | 5 | 4) team set goals and milestones | 4 | 5) people listened to each other | 4 | 6) leadership was shared among the members | 4 |