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Wind Turbine Lab Report

Submitted to:

Dr. Bixler

GTA Sarah Hulbert

Created by:

Team P

Joseph Blust

Jerry Ding

Zach Kahlig

Dharoov Verma

Engineering 1181

The Ohio State University

Columbus, OH

4, April 2017

Lab Report- Wind Turbine Lab 2

Executive Summary

The purpose of this lab was to explain the different methods and applications that are used in finding the best wind turbine configuration that would be used to power a residential complex. This taught us the different theories and understandings involved in the process. The group assessed and evaluated theories such as Bernoulli's principle and different trends related to wind velocity, wind power, pressure, pressure difference and wind turbine power output. Wind velocity, pressure, wind power, different blade configurations, number of blades, and the angle at which it is located around the center are all central factors in determining the highest turbine power output. Once these ideas were drafted the team then gathered the evidence to produce a wind turbine to meet the specifications provided by the residential complex. This included 40 houses each with an energy demand of 50 KWH/day, 77 meters diameter turbine with a 25% efficiency, and a blade length of 32 meters. We used this to determine if it was sustainable to use wind energy to power the houses.

The results achieved in this lab led to insightful understandings of the mechanisms and relationships between wind speed, pressure, power, and wind turbine efficiency range. First, it was learned that wind speed is indirectly proportional to the pressure because of Bernoulli's principle. As wind speed increases the pressure decreases so that causes the difference in pressure to rise. This is reason that blades spin and a factor in considering what type of blade model to design. Then, the relationship between wind speed and wind power was discovered to be directly proportional. As wind speed increases so does the wind power. These different relationships are displayed in Figures 1,2,3, and 4.

The recommendations that were analyzed in this lab was to essentially find a location that produced the most wind power. This was decided to be at the place of Sandusky, Ohio with an average wind speed of 7 m/s. This was validated to be the largest wind speed situated on the diagram. Operating on that evidence, our group constructed a wind turbine that produces the most wind turbine power output so that it will be able to electrically power the energy needed to power as many houses as possible. To find the greatest power output construct a blade design that created the most power. After that has been established, incorporate as many blades as you can on the wind turbine because it was discovered that more blades equals more power output produced.


Table of Contents

Introduction ................................................................................................1

Experimental Methodology ........................................................................1

Results .......................................................................................................2

Discussion................................................................................................10

Conclusion and recommendation ............................................................11

Appendix ..................................................................................................11


Introduction

The Wind Turbine labs introduced students to basic concepts in fluid flow, including the relationship

between pressure, velocity and wind energy, along with generated power and efficiency of wind

turbine, used during the design process. The purpose of this experiment is to determine the amount of

power that can be produced by a 77 m diameter turbine with a 25% efficiency. The blades have a length

of 32 m and the overall height of the turbine is 80 m. The amount of energy needed for a house in this

complex is 50 KWH/Day. A residential complex with 40 houses is looking to power its energy needs using

wind energy. The team has to find out whether this wind turbine power the entire residential complex,

If not, the team has to find out what percentage of the needed power can be supplied by the wind

turbine. Assuming that the wind turbine operates all day and the wind speed is a constant.

Experimental Methodology

Wind Energy in general refers to the kinetic energy present in the wind. The wind push against the blade

and causes the blade to rotate. This kinetic energy in wind is converted to mechanical energy of rotating

rotors. The generator in the wind turbine can then convert this mechanical power into electricity. As the

wind turns the blades it rotates the shaft which turns the gears in the generator to create electricity. The

largest component of the turbine is the rotor which consists of the blades and their point of connection.

As velocity of a body of gas increases, its pressure decreases. This concept is realized in the Bernoulli's

principle. As a result, the blade is lifted and it enhances the rotation of modern wind turbines.

The experiment used the wind tunnel flow tube, wind source fan, pitot tube and static tube to find out

the wind velocity for different radial position and find out the power using this information. Later the

experiment will measure the power of the wind source as a function of wind speed. Then the

experiment is conducted to compare the power output between the two and three blade turbines.

On the second section of the lab, each team member created their own individual turbine blade with

any geometry. The only requirement for the blade was that it could be no longer than 2 inches in order

to fit in the testing tunnel. The blade was inserted into a groove on the hub. Each blade design was

tested at 12V. The turbine blade design that produces the greatest power at 12 V is selected. Using the

selected turbine blade design five more balsawood turbine blades are made. Using the 30 ̊ pitch hub, the

team measured the output for two three and six blade system to determine the arrangement/number

of blades that produces the maximum amount of power. The arrangement that produced the maximum

power was selected and used on the hub with a 45 ̊pitch to find out the power output in that

configuration.


Results

Table 1: Wind Speed as a Function Volts and Radial Positions of Wind Tunnel

Radius (cm) *

Wind Speed (m/s)

Pressure Difference, ∆P (Pa)

r 6 volts 9 volts 12 volts 6 volts 9 volts 12 volts 0 4.48 7.24 8.65 12.945408 33.809352 48.2605125 1 4.40 7.15 8.38 12.4872 32.9740125 45.294738 2 4.55 7.10 8.55 13.3531125 32.51445 47.1511125 3 4.72 7.65 9.00 14.369568 37.7470125 52.245 4 5.05 8.15 9.75 16.4491125 42.8425125 61.3153125 5 5.15 8.25 9.90 17.1070125 43.9003125 63.21645

Table 1 illustrates the relationship between pressure difference and wind velocity as well as the

relationship between radial position and wind velocity with increasing increments of voltage. As wind

speed increases due to the radius increasing, the pressure difference begins to also increase. This occurs

because of difference of pressure equation(1). When the radius of the pitot tube increase from the

center of the tunnel, the wind speed increases. This is due to fluid mechanics and explains the reason

why two vertical papers will come together when you blow air between them. This relates to the theory

of Bernoulli's Principle in that as wind speed increases the pressure decreases and that pressure

difference increases. The following equations were used to calculate the values in Table 1. The sample

calculations can be found in the appendix in equations 1.

Difference Pressure P=(A*ρ*(Air)*V22)/2 Pressure Difference(Pa)=

Area of Blade(m2)*Density of

Air(1.29

Kg/m3)*Velocity(m/s)^2/2


Figure 1: Wind Velocity vs. Pitot Tube Radial Position

Figure 1 illustrates that the measure of the wind speed that is closer to the walls of the tunnel are higher

than the wind speed near the middle. This also effects the pressure as there is less pressure on the

outside versus the inside. This describes an indirectly proportional relationship. This trend illustrates the

fact of why the blades rotates; difference of pressure.

Figure 2: Pressure Difference vs. Pitot Tube Radial Position


Figure 2 displays the relationship of pressure difference and radial distance. The trend is that both

pressure difference and radial distance increases and this is due to the theory of Bernoulli's principle.

This describes a directly proportional relationship.

Table 2.1: Wind Velocity and Wind Power as a Function of Radius and Volts

Radius (cm) *

Wind Velocity, v(r) (m/s)

Δ Area (cm2)

Wind Power (Watts)

r 6 volts 9 volts 12 volts Δ A 6 volts 9 volts 12 volts 0 4.48 7.24 8.65 0.79 0.005 0.019 0.033 1 4.4 7.15 8.38 6.28 0.035 0.148 0.238 2 4.55 7.1 8.55 12.57 0.076 0.290 0.507 3 4.72 7.65 9 18.85 0.128 0.544 0.886 4 5.05 8.15 9.75 25.13 0.209 0.878 1.502 5 5.15 8.25 9.9 31.42 0.277 1.138 1.966 Total 95.03 0.729 3.017 5.133

Total Area, A =

0.009503 m2

Table 2.1 displays the development of wind power as the wind velocity increases. As wind velocity

increases so does the wind power. It is also seen that as the radius increases so does the wind velocity.

This concurs with Figure 1.

Table 2.2: Estimated Average Wind Position

For 6 Volts For 9 Volts For 12 Volts Units

Average Wind Velocity

4.92 7.90 9.43 m/s

raverage 4 4 4 cm

Table 2.2 displays the estimated average wind positions which were used in the following tasks. These

values are estimated by matching the average wind speed values See in Table2.1) to the corresponding

radial positions on the graph(See in Figure1).


Table 3: Wind Velocity and Wind Power with varying Voltages Information

Power Supply Voltage

Wind Velocity (m/s)

Calculated Wind Power (W)

Volumetric Flow Rate (m3/s)

Mass Flow Rate (kg/s)

6 4.5 0.558368438 0.04276493 0.05516676 7 6.73 1.867792007 0.063957329 0.082504954 8 7.45 2.533682187 0.070799717 0.091331635 9 8.05 3.196472416 0.076501708 0.098687203 10 8.52 3.7896762 0.080968267 0.104449065 11 9.07 4.571989045 0.086195092 0.111191669 12 9.36 5.024708433 0.088951054 0.11474686

The calculated wind power, volumetric flow rate and mass flow rate with each corresponding power

supply voltage is contained in Table 3. While measuring and recording wind velocity, the raverage from

Table 2 estimated at 6 V was used for the 6, 7 and 8 Volt settings. The raverage at 9 V was used for the 9,

10 and 11 Volt settings. The raverage at 12 V was used for 12V. As shown in the table 3, calculated wind

power, volumetric flow rate and mass flow rate all increasing in accordance with the power supply.

Figure 3: Calculated Wind Power vs. Wind Velocity


Figure 3 displays the relationship of wind power and wind velocity. As shown in the graph, wind power

increases while wind velocity increases. In addition, although the equation shows that the wind power is

proportional to the cube of wind velocity, the line looks like a straight line since the value of wind power

is incredibly small.

The following equations were used to calculate the values in Table 3. The sample calculations can be

found in the appendix in equations 2,3, and 4.

Wind power P=½ × A × ρ × v3 Wind power(w)=½*Area

of the wind turbine(m2)*Density of

air(kg/m3) *Wind velocity(m/s)3

Volumetric flow rate Q=v × A Volumetric flow rate(m3/s)=

Wind Velocity(m/s)*Area of the

wind turbine(m2)

Mass flow rate m=ρ × Q Mass flowrate (kg/s)=Density

of air(kg/m3)*Volumetric flow

rate(m3/s)

Table 4: Turbine Power as Function of Wind Velocity

Power Supply Voltage

Wind Velocity From Table 3 (m/s)

Wind Turbine Power Output (watts)

2 Blades 3 Blades

6 4.5 0.013 0.017 7 6.73 0.027 0.043 8 7.45 0.038 0.060 9 8.05 0.047 0.072 10 8.52 0.057 0.085 11 9.07 0.065 0.100 12 9.36 0.075 0.120


Table 4 shows that a configuration of 3 blades produces more power output than a configuration of 2

blades. The relationship between turbine power and wind velocity is directly proportional. Since there

are more blades, the wind turbine is able to spin faster than the 2 blade configuration according to each

wind velocity used in the experiment.

Figure 4: Winds Velocity vs. Wind Turbine Power Output (W)


As shown in Table 5 below, blade design number 1 generated the highest power output (W) of the four

blade designs tested. As a result of this, the blade design 1 was then used for the rest of the experiment.

(See Appendix for photos of the blade designs)

Table 5: Power Output of Each Group Member's Blade Design

Blade Design No. Power Output (watts) Designer

1 0.0053 Blust 2 0.0039 Kahlig

3 0.0025 Verma

4 0.0049 Ding

Table 6 states the power output of blade design 1 with 2, 3 and 6 blades. As can be seen in the data, 6

blades produced the highest power output in

Table 6: Power Output of Blade Design 1 With 2, 3 and 6 Blades

Design Power Output (watts)

2 Blades 0.031 3 Blades 0.038 6 Blades 0.042

After determining that 6 blades produced the maximum power output with blade design 1, 6 blades

were then tested in a 45° hub (See Appendix "Blade Design 1: 6 Blades 45° Hub"). The values for this

table were determined with the fan motor voltage set at 12 volts.

Table 7: Power Output as a Function of the Angle Hub Information

Angle Power Output (watts)

30o 0.042 45o 0.014

According to the results in Table 7, the angle of 30 degrees is more efficient that the angle of 45 degrees

because it produces more power output.


Discussion

After experimenting different trials and using different methods to produce the highest power output,

the following analysis can be concluded and analyzed from this lab.

It is inferred from the data that a location of high speed also has high wind power. This is shown in Table

1. Having a greater number of blades produces more wind turbine power output. This is found in Table

6. This trend is described as directly proportional. Another trend is that the 30 degree hub produced

more of a power output than a 45 degree hub.

Numerous faults can be found in this lab that would generate potential error. First, not every blade was

the same that was carved. This can create a small error in the efficiency that each blade would make as

the pressure difference could be different for each blade. To solve this, a machine would be needed to

cut out the same exact design as the first blade. This would reduce inaccuracies. Another error is that

the voltage meter could be calibrated incorrectly and could affect an error in the wind velocity, This, in

turn, would produce inaccurate calculations for wind power. To solve this, make sure the voltage meter

is calibrated to meet the specifications.

As was expected, our experimental values are close to the theoretical values that we were given.

Although this is correct our calculated values for our efficiency is off due to potential error. In Table 6

our power output for a 6 blade configuration is 0.042 Watts. This is when the wind velocity is at 9.36

m/s or at its maximum. The calculated wind power for that situation is 5.024 Watts. Dividing the power

output of the blade by the wind power and times by 100 gives you an efficiency of around 8%. This is

less than the theoretical value of 25% percent that was given. This could be due to the fact that the

technology for a real life turbine would be better and therefore produce a greater efficiency.

According to the map given in the lab procedure the best wind speed is near the Lake Erie by the cost of

Sandusky. Moreover, due to the lake there is a constant temperature difference between the land and

water creating a wind flow. Therefore the team selects this region as the suitable place to install a wind

turbine. The wind speed here is 7 m/s.


To calculate the power of the wind we can use the following formula.

P=(½)ρAv3

P= wind power

ρ =the density of air at standard temperature and pressure, 1.29 kg/m3

A= the area swept by the turning turbine blade.

The diameter of the turbine is 77m. The blades have a length of 32 m and overall height of the turbine is

80 m.

Therefore the area swept by the turning turbine blade is:

π*(77/2)2-π((77/2)-32)2 = 4523.89m2

Therefore the wind power is:

P = (½)*(ρ*A*v3)

P = (½)*(1.29*4523.89*73)

P=1000843.56 watst

The wind turbine has 25% efficiency.

Therefore, the power output is:

Power output=P*0.25

Power output= 250210.89 watts = 250.21089 kilo watts

The total power generated by the wind turbine is 250.21089 kilo watts.

Total power generated in a day is 6,005.06 kwh/day

Total power required by the 40 houses is 40*50 kwh/day=2000kwh/day

The power generated exceeds the power required therefore the wind turbine can efficiently power 40

houses.


Conclusions & Recommendations

This lab focused on producing the largest turbine power output to generate enough energy to be able to

power a residential complex. This experiment helped to identify the correct process and methods to

formulate the finest wind turbine. The results that were identified compared the relationships of wind

speed, pressure, wind turbine power output, blade design, number of blades, angle of blade, and wind

power. Wind speed is indirectly proportional to pressure. This causes a pressure difference. Wind power

increases and wind speed rises. Wind turbine power output increases as wind power rises. Increasing

the number of blades produces a greater power output. A 30 degree blade design produced greater

power output than a 45 degree design. With these ideas in mind, the group drafted a windmill that

maximized these specifications. Namely, a wind turbine that would be compiled to have a 30 degree

hub, 6 blades, and at a location and situation that produced the most wind speed.

This produces the most wind power and ultimately the most power output. In Table 6 the power output

of 0.042 Watts is shown to be the greatest and it has a 6 blade configuration. In Table 3, it was shown

that having a higher velocity produced high wind power. This highest wind velocity is 9.36m/s and that

produced the highest wind power of 5.025 Watts. A good recommendation would be to choose a

location that produced the highest wind velocity and to implement a blade design that has the greatest

power output. This is a design that is thick in the center and thin on the outside. This is because the

higher pressure is near the center so have a blade area that is greater there produces more spin. Also

having more blades creates more power output as is shown in Table 6.

Some error that could be resolved is to calibrated the voltage meter properly. This, in turn, would make

the wind power more accurate which would produce more accurate efficiency results for the wind

turbine. Another error is the seal between the motor fan and the tunnel is not perfect. This allows for

some air to escape and ultimately causes the pressure to be different. A way to resolve this is to make

sure there is a strong seal between the two materials.


References

"Wind Turbine Blade Design" (2012, September 6). <http://www.mdpi.com/1996-1073/5/9/3425/pdf>

Engineering Education Innovation Center: Engineering Summer Experience. “Green Energy &

Sustainability”. Hitchcock Hall, Columbus. 2012. PowerPoint

A Wind Energy Pioneer: Charles F. Brush. Danish Wind Industry Association. Retrieved 2008-12-28.

Barber, David. "Small Wind Turbine Components." eHow. Demand Media, 08 Nov. 2010. Web. 29 June

2012. .

"Wind Energy Basics." Wind Energy Basics. Wind Energy Development Programmatic EIS, n.d. Web. 29

June 2012. .

"How Wind Turbines Work." Wind Program, Department of Energy, 18 Oct. 2011. Web. 10 July 2012. .

"Offshore Development." Ohio.gov. Ohio Energy Resources Division, n.d. Web. 25 July 2012..

Wilke, Dillion. "Charles Brush." Charles Brush. Humboldt State University, 5 May 2011. Web American

Municipal Power, < http://amppartners.org/generation-assets/wind- power/>


Appendix

Sample Calculation

Difference Pressure Δ P=A*(ρ(Air)V22)/2 Pressure Difference(Pa)=

Δ P=(1.29kg/m * (5.05m/s)2)/2 (Area of blade)*(Density of Air(1.29 Kg/m3)

=16.4491125Pa *Velocity(m/s)^2)/2

(1)

Wind power P=½ × A × ρ × v3 Wind power(w)=½*Area

P= ½ ×0.009503m2× 1.29kg/m × (4.5m/s)3 of the wind turbine(m2)*Density

=0.558368438w of air(kg/m3) *Wind velocity(m/s)3

(2)

Volumetric flow rate Q=v × A Volumetric flow rate(m3/s)=

Q=4.5m/s × 0.009503m2 Wind Velocity(m/s)*Area of the

=0.04276493m3/s wind turbine(m2)

(3)

Mass flow rate m=ρ × Q Mass flowrate (kg/s)=Density

m=1.29kg/m × 0.04276493m3/s of air(kg/m3)*Volumetric flow

=0.05516676kg/s rate(m3/s)

(4)

Blade Design 1: 30° Hub


Blade Design 1: 3 Blades 30° Hub



Team Meeting Notes


Date: 4/3/2017

Time: 5:30PM (Face-to-Face)

Members Present: Joseph Blust, Jerry Ding, Zach Kahlig, Dahroov Verma

Topics Discussed: Lab 6A and 6B

Objective: Discuss the plan for and complete the Lab Report for Lab 6 (Wind Turbine).

To do/Action items:

• Assigned roles

• Results Section (All group members)

• Tables (Blust, Ding)

• Photos (Blust)

• Figures (Verma, Ding)

• Discussion (Verma, Kahlig)

• Conclusions/Recommendations (Kahlig)

Reflections:

• By understanding our roles and working well as a team, we were able to complete the Lab

Report.

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