Anthony Benasco, Hulon Reid, and Brody Holloway

Senior Design Final Proposal

Advisors: Dr. Cris Koutsougeras and Dr. Junkun Ma

Spring 2014

Abstract:

Wind turbines, along with other clean alternative energy methods, have been utilizing the

planet’s natural resources to extract energy in a form that is usable and meets our daily

necessities. In terms of creating this energy, a wind turbine converts the kinetic energy from the

wind into mechanical energy from the rotating blades; furthermore, it then converts into

electrical energy. However, there are numerous unique turbines with regards to its design

schematic, efficiency, size, and many more. Commonly, these turbines consist of a horizontal

shaft, yet recent experiments found that a vertical setup can provide even more efficiency by

producing a greater output.

Introduction/Purpose:

Over the past centuries, technological advancement has been undergoing an enormous

transformation with new research discoveries and innovative inventions. With this in mind, we

are always looking for new methods of improving our lifestyles and the world we live in with

these new technologies and machineries. This project’s purpose is to seek a new prototype

design that not only has a distinctive design but promotes an alternative technique to achieve the

most efficiency possible.

The concept behind the prototype wind turbine is very straightforward. The blades are

simply flat panels made of light, heavy duty material, such as carbon fiber, stainless steel, or

aluminum. The orientation of these panels will change with respect to the wind direction. One

blade will be in the vertical position for two quadrants, while the opposite panel will be

positioned horizontally for the other two. These design schematic allows two panels to coincide

with one another in order to produce higher efficiency with more rotations per minute (rpm).

The mechanical aspect of this machine will be one of the more challenging obstacles in the

component design and construction phase, which is discussed more in detail below. It is very

vital for the system to be capable of adjusting to the variations in wind direction and speed

because if it cannot achieve this, it defeats the purpose of the installed system components and

the mechanisms behind the design.

Initial Design Phase:

Currently, the wind turbine system is in the design phase with researching the necessary

components and physical forces that could affect and potentially cause the system to fail. Since

the blades have to be adaptive to the wind deviation in magnitude and direction, the components

being examined are both the CAM System and weather vane. This weather vane must be

installed at the peak of the structure to notify the system in these changes in the wind. The CAM

System is a mechanical instrument that will initiate the flipping action of each blade of the wind

turbine. The CAM System design is essential for the turbines success. Without a proper design,

the panels will flip into an improper arrangement that will slow down the rpm; thus, less output

can be attained. Since the CAM design will be fixated—never changes—there needs to be a

corresponding device that will rotate this CAM into the proper orientation. This can be

accomplished with a gear that is electrically motorized to rotate the CAM when the wind

direction changes. Since the system needs to be continuously updated with the current wind

direction, there is a weather vane that will be installed at the top of the shaft. The rotation of the

weather vane will notify the system that adjustments with the CAM’s orientation need to be

made. This is accomplished by a very small device known as a micro switch. Two micro

switches will be placed 180 degrees apart from one another. They will send electronic signals to

the electric motor whose responsibility is solely rotating the gear. Moreover, it will allow the

CAM to be orientated in the appropriate manner. As shown above, after given a specified wind

direction, there is only one airfoil panel that will be completely vertical to capture most of the

winds force, building a pressurized cross-sectional area on one side of the shaft. This, in return,

creates a rotational force that will provide us utilizable energy through the conversion of kinetic

(mechanical) energy to electrical energy. The electrical energy is generated by the alternator,

which is located at the base of the shaft with most of the complex components in the system.

There is a pulley system that connects directly to the shaft pulley, allowing energy to be created

through mechanical work.

The system can be better understood by getting a bird’s eye view of the system’s airfoil,

and how each coincides with one another to create a less resisting system, which creates a unison

circular movement around the axis of rotation. There are four panels overall, each installed

directly to the shaft at 90 degrees apart. One panel is perfectly vertical for a 90 degrees interval.

This portion of the quadrants will provide the system the most rotational force, so it must remain

in this fixated position. The panel will begin its flipping motion once it begins to approach the

first quadrant (shown in the diagram). The CAM plate will begin to slope downward to allow

this mechanical flipping motion to take place. The flipping motion will either commence or

cease at the end of the CAM’s ramp (between quadrants II/III and IV/I). The panels will remain

perfectly in the horizontal position until it reaches the end of quadrant II. This CAM design was

determined theoretically the most efficient, but further experimental evaluation will confirm

what framework will be the constructed for the wind turbine.

COMSOL:

To gain a more practical understanding with regards to the wind turbines efficiency and

stress/strain load, an additional software program was utilized to perform theoretical

calculations, known as COMSOL. It provides visual and mathematical analysis that is vital to

our system. The first portion of the calculation was used to measure the amount of pressure

(Pascal’s) in a given cross-sectional area. The diagram below is a simple representation of an

airfoil perpendicular to the wind direction, providing the maximum pressure. However, the goal

behind the usage of COMSOL is to compare theoretical values as one variable is adjusted in each

scenario. This information gives an insight of how large these airfoils must be in order to

achieve optimal output readings.

This project will continue onto the next semester with much more emphasis on the

practical construction of the wind turbine. There are a series of calculations that need to be

complete within the allotted time given, such as theoretical work, proper sizing of airfoils, more

detailed shaft structure, and the best CAM system design. The theoretical work must be

calculated via COMSOL to produce the results needed. It will remain as one of the most

challenging aspects to the design phrase. There could be potential changes to the design of the

wind turbine structure if there is a need for improvement. The CAM system will be tested

experimentally by producing a series of unique design. Each system will be influenced by the

same magnitude of wind velocity, and the design that promotes the highest rpm values will, in all

likeliness, be used in the construction phase. There are a few calculations in the following

section that remain to be computed, but will be solved in manner of proper time.

Calculations:

Chain Design:No. 80 Chain, 1 inch pitchLength = 100 pitches, 100 inch ChainCenter Distance = 30.26 inch (Maximum)Sprockets = Large, 59 teeth, D = 18.789Small, 17 teeth, D = 5.442Input RPM @ 3 MPH = 38 RPM (Estimated)Output RPM = 130 Minimum, 2500 MaximumRatio = 130 RPM / 38 RPM = 3.421Sprocket for DC-540 Motor (N1) = 17 teethSprocket for Wind Turbine Shaft (N2) = N1 * RatioN2 = 17 * 3.421 = 58.2 since an even number of teeth is not recommended, we chose a sprocket with 59 teeth.Actual expected output speed = 38(59/17) = 131.9 RPMPitch Diameters of the sprockets. We chose a 1 inch pitch chain. (p = 1)D1 = p / sin(180/N1) = 1 in / sin(180/17) = 5.442 inchD2 = p / sin(180/N2) = 1 in / sin(180/59) = 18.789 inchNominal center distance = 30 pitchesRequired chain length (L) = 2C + [(N2+N1)/2] + [(N2-N1)^2 / (4*PI^2 *C)L = 2(30) + [(59+17)/2] + [(59-17)^2 / (4*PI^2*30)] = 99.49 pitchesChain Length = 100 pitch, 100 inchCenter Distance © = .25[L – (N2+N1)/2 + Sqrt[(L – (N2+N1)/2)^2 – 8(N2 –N1)^2/(4*PI^2)]C = .25[100 – (59+17)/2 + Sqrt[(100 – (59+17)/2)^2 – 8(59 –17)^2/(4*PI^2)] = 30.262 Pitches

C = 30.262(1 in) = 30.262 inch (Maximum)The Angle of wrap (@) for the chain on each sprocket.@1 = 180 – 2 sin^-1 [(18.789-5.442) / 2(30.262) = 154.52 degrees@2 = 180 + 2 sin^-1 [(18.789-5.442) / 2(30.262) = 205.48 degrees

Shaft Design:We will use a Car Axle for the shaft that is attached to the Wind Turbine and drivingsprocket.Length = 92 in, Width = 4 inProperties of ShaftTensile Strength = 55 KSI, Yield Strength = 30 KSI, Ductility = 25%Size Factor (Cs) = .75Reliability Factor (Cr) = .75 (99.9% Reliability)Endurance Strength (Sn) = 20 KSIActual Endurance Strength (Sn’) = SnCsCr = 20*.75*.75 = 11250 PSIDesign Factor = 2@ 3 MPH the Torque = 63000(.0065 HP) / 38 RPM = 10.8 lb-in@ 10 MPH the Torque = 63000(.0754 HP) / 126 RPM = 37.7 lb-in@ 20 MPH the Torque = 63000(.5104 HP) / 252 RPM = 127 lb-inForce on ShaftForce = T / D = 127 / 12 = 10.58 lbEFy = 0EFx = 0 = Fxb - Fxa = Fxa = 10.58 lb and Fxb = -10.58 lbMax Stress = Stress Concentration Factor (Kt)*[4*Vertical Shear Force (V) / 3* Area of cross section (A)] = 2*[(4*10.58) / (3*1.571)] = 17.96 PSIA = (PI*D^2 / 4) = (PI*2^2 / 4) = 1.571 in^2V = Sqrt[Resultant Y^2 + Resultant X^2] = Sqrt[0^2 + 10.58^2] = 10.58 lbKt = 2N = .577(Sn') / Max Stress = .577(11250) / 17.96 = 361.43Required shaft Diameter (D) = Sqrt[2.94 (Kt*V*N) / Sn’]D = Sqrt[2.94(2*10.58*361.43) / 11250 = 1.414 inchTip Speed Ratio (TSR)TSR = Tip Speed of Blade / Wind SpeedTip Speed of Blade = (2 * PI*r) / TimeMax Power = (4* PI) / n

Optimal TSR = 6 for a two blade Wind Turbine6 = Tip Speed of Blade / Wind Speed@ 3 MPH or 1.34 m/sTip Speed of Blade = 6 * 1.34 m/s = 8 m/s Tip Speed of Blade = (RPM * PI * D) / 60Diameter (D) = 4m RPM = (Tip Speed of Blade * 60) / (4 * PI)RPM = (8 m/s) * 60) / 4 * PI = 38 RPM

Reacting Forces for Components on Platform

The platform will be 3 feet with a two feet overhang for the gears, chain, and motor. There will be a concentrated load of 270 pounds on the center of the three feet. There will also be a force of 30 pounds on the overhang of the two feet (gears, chain, and motor).

Forces in the x-direction equals zero: F(x) = 0

Forces in the y-direction: F(y) = 0 = - R1 – R2 + 270lbs + 30 lbs

Moment of Bending is calculated by:

0 = (270lbs)(1.5ft.) + (30lbs)(5ft) – R2(3ft)

= (405 lbs-ft) + (150 lbs-ft) – R2(3ft)

= (555 lbs-ft) – R2(3ft)

R2 = 555 lbs-ft / 3ft = R2 = 185 lbs Reaction force on the end of plate before overhang

F(y) = 0 = - R1 – (185 lbs) + (270lbs) + (30lbs)

Solve for R1 R1 = 115 lbs Reaction force at the far left end of plate

Approximate Weights for Vertical Wind TurbineComponent Weight (lbs)

Vehicle Axle (Shaft) 100DC -540 Low Wind Permanent Magnet

Alternator11

Sprockets and Chain 15Louvers 100

CAM System 25Bearings 4

Relay Box 3Approximate Total Weight 258 lbs

BudgetProduct Dealer Cost

DC – 540 Low Wind Permanent Magnet Alternator

Wind Blue $199.00

1000 Watt Wind Turbine Generator Grid Inverter

EBay $259.00

59 teeth Driver Sprocket No. 80 1 inch pitch

WBC Industry $240.78

17 teeth Driver Sprocket No. 80 1 inch pitch

WBC Industry $25.58

Miscellaneous (bearings, electronics, circuit, etc..)

N/A $800.00

Approximate Cost : $1524.36

Technical Specifications for a DC- 540 Low Wind Permanent Magnet Alternator

This PMA unit features a completely brushless design that eliminates the need for

maintenance and reduces friction, specially wound Low RPM Output stator. Super Strong N50

grade Neodymium rare earth magnets are at its core to replace the inefficient electromagnetic

field coil. Zero Cogging It is built using Brand New GM Delco alternator components including

NEW Stator Coils, factory balanced Stainless Steel shafts and New Rotor Pole Shoes.

Replacement bearings and parts will be available for years. Built-in rectifier. (DC output is

unregulated) This unit is perfect for direct drive wind turbines in areas that only see 5-15 MPH

winds on average. Not recommended for motor driven or geared up wind use. Please select our

DC-512 model for use with engine driven applications and DC-520 for geared up wind use. Built

to last with new bearings and a baked on clear ceramic finish that will last for years in harsh

outdoor environments. A 90 day full replacement warranty on all units (warranty void if PMA

has been opened or tampered with) produces 12 Volts at just 130 RPM and the voltage keeps

going up from there (see chart below). It makes over 350 volts at 2500 RPM. Also, it produces

up to 15 amps into a 12 volt battery at 2000 RPM.

Dimensions of the DC – 540 Low Wind Alternator

Turbine Construction:

In order to promote the most efficient turbine, the structure needs to have a light weight

airfoil design with a superior base support foundation that will withstand substantial hurricane

force winds. The base portion of the structure is currently in the planning phase. This job is

being conducted by a small group of construction engineers. To begin the design, some factors

that need to be acknowledged include the overall weight of the turbine, composition materials,

potential sizing (airfoil and shaft length), and many others. The height of the turbine needs to be

overshadowing any nearby complexes and trees. The approximation on the height is roughly

between 40-60 feet. The width of the airfoils is also an essential factor to consider. Basic

knowledge of fundamental physics principles, the amount of torque that can be created by

contact with the airfoil increases as the wingspan extending from the axis of rotation increases.

It will take less wind force to cause the turbine to rotate and create utilizable energy. However,

with this in mind, the weight of the turbine will also increase, making it more difficult for

rotation to occur. There is a certain wingspan that will give the turbine the most efficiency. The

initial design wingspan was to construct the airfoils at around 16-20feet from one airfoil to

another. Although durability is a huge aspect towards the airfoil construction, a light weight

material composition needs to be included. A variety of materials were considered for the

design, such as sheets of aluminum, carbon fiber, steel, and so on. After a wide range of

searching and measuring the pros and cons, the airfoil was decided to be made of corrugated

plastic. This material composition meets the necessary requirements to prepare the airfoil

devices. On several websites, these plastics have a single dimension that reached 8 feet by 4 feet

which is very close to our original intentions. Along with durability, the corrugated plastics have

a much lighter composition compared to aluminum and steel. Carbon fiber may have a good

advantage to the corrugated plastics, but cost becomes another issue in this decision process.

With this project ranging from several hundred to thousands, the cost of carbon fiber is relatively

expensive. Corrugated plastics can range from $20-60 with no adjustments needed for the

sizing.

This vertical wind turbine consists of four different panels on the same plane. The

dimensions of the frame were designed by the max amount of wing span I could achieve with the

amount of material given. Aluminum tubing (1 inch by 1 inch) was chosen to be the material

used for the frames because of its lightweight and durability. The dimensions of the frame is 44

in. by 95.5 in (inside to inside) and 46 in. by 97.5 (outside to outside) to be exact. A piece of

aluminum tubing is placed in the center of the frame to reduce twisting, stabilize the frame, and

to be a stopping point for the air foils. After the dimensions were cut, I took all the frames to a

welding shop to be fabricated. The dimensions of the frame depended on the size of the air foils

and how many were going to be used. The frames would then be attached to the shaft.

We chose to use corrugated plastic (.5 in. thick) for the air foils. The air foils

constructed out of Corrugated Plastic Sheets will open and close by wind pressure, and it will

swivel on a rod attached to the frame. Four pieces of corrugated plastic (12in. by 95 in.) are

used in each frame to act as a louver system. At the center of each corrugated plastic piece, a cut

out was made (1 ¼ in. wide and 6 in high) because of the aluminum tubing that was placed in the

center to stabilize the frame and so each piece would overlap properly. Each piece of corrugated

overlaps each other by 1 in. The connectivity of the airfoils becomes rather simple since we

chose to use the corrugated plastic design. The unique characteristic of the plastic is due to the

square concavities on the interior of the sheet. This allows easy installation of the airfoil arms

that extends from the shaft to the outer aluminum support frame. The airfoil arms are being

made out of aluminum rods that will slide into these concavities and attach directly to the frame

support. Simplicity is vital to making the turbine successful since there are many mechanical

parts involved with the turbine functionality. An aluminum rod (5/16 in.) is used to connect the

corrugated plastic to the aluminum tubing. Each rod was cut 98.5 in. and was inserted through

the corrugated plastic and through the aluminum tubing. On one end of the tubing, the aluminum

rods comes out 1 inch passed the tubing. A hole was drilled through the rod, so a pin could be

placed in order for the rod not to back out. Spray foam will be applied inside the tubing, so

grease fittings can be installed on each end of the rod so the four different corrugated plastic

sheets can swivel. The spray foam will ensure that the grease will stay in the one spot applied

and not run down the tubing. This will allow the rods to be greased and create less friction.

Weights

4 Corrugated Plastic Sheets 15 lbs.

Aluminum Tubing 15 lbs.

Total Weight of One Panel = 30 lbs * 4 panels = 120 lbs. Up Top

Each panel covers 31.15 square feet.

All of the panels are fabricated with the air foils installed inside. There are only a few

steps left in order for all of the panels to be completed. Spray foam needs to be applied in the

inside of the tubing and the grease fittings need to be installed in order for the panels to be

complete.

The estimated cost for the air foil construction and the pulleys for the shaft and

transmission system are listed below:

Supplies: Airfoil ComponentsQuantity Item Source Price

4 4' x 8' Corrugated Plastic Sheet 10mm

Sign World $140.00

8 8’ U Profile Farmtek $5.738 1/8” x 4’ Steel Rods Hardware World $8.714 1” x 1’’ Square

Aluminum Tubing 10’Brumfield Welding $60

Welding Brumfield Welding $40Pins Harbour Freight $10

16 5/16” Aluminum Rods

Bayou Metal N/A

32 Grease Fittings Harbour Freight $20Shipping $39.98

Total $235.96

Supplies: Shaft and

Transmission System Components

Quantity Item Price2 10.25 O.D 1 Bore 1 Groove

Pulley$65.90

1 2.95 O.D. 1 Bore 1 Groove Pulley

$7.75

2 1” Pillow Block Bearing $13.902 50” B V-Belt Type B47

5L500 Classic$12.10

1 70” B V-Belt Type B67 5L700 Classic

$8.35

2 68” B V-Belt Type B65 5L680 Classic

$16.20

Shipping $18.66Total $142.86

Overall Progress:

The initial design phase of the wind turbine was slightly altered to promote a more

simplistic and effective structure design. The mechanism that was responsible for the flipping

action in the beginning of the design phase was the CAM system. Due to limited supplies of

materials and cost-effectiveness, the airfoil schematic was changed. During the process, the

design was finalized, and the plan was to allow the highest resistant airfoil to allow the rotation

to occur, whereas the lowest resistant to flip its airfoils. This setup follows the exact principles

defined earlier on with the CAM setup. Rather than having a complex mechanical system to

initiate the turbine, an unsophisticated design is established. The side with the greatest air

pressure will determine the direction of rotation around the shaft. With this in mind, the

following diagram provides a better visual of how this principle will work in our favor.

Basing off the louver airfoil schematics, a series of airfoils will be installed to a 4’ by 8’

dimension aluminum framework. The center perpendicular aluminum tubing will provide a

structural advantage since the length of each airfoil is rather large. The material is more likely to

undergo a certain amount of stress in the center of the corrugated plastic; in other words, it is

more probable to fail and give way from a high intensity of wind. With regards to the above

diagram, if the specified wind direction were to impact the airfoil from left to right, the lower

end of the airfoils will be laying on top of one another at each of their axis of rotations.

Resistance would then be at its greatest, allowing the airfoils to be pushed by the wind; However,

if the wind direction where to impact from the back side of the airfoil, there is little to no

resistance on the airfoil. The airfoils will flip to permit the wind to pass through. No rotation

will occur from this impact.

An important aspect to the structural stability of the wind turbine will depend highly on

how it is mounted to a base support. The base support was made from steel beams, which are

very sturdy and are typically used as supporting materials. The outer dimensions of the base are

4’ by 4’. This does not put a tremendous amount of weight on the lower portion that will hold

this structure 50+ feet in the air, and it will fit every component needed to make this turbine an

active energy producer.

Along with the base support, there will be a series of guide wire connections that will be

installed to provide even more support in case of excessive wind and to balance the weight of the

airfoils on each end of the shaft. There will be an overall of two different guide wire systems for

this setup: 1) lower shaft to base support and 2) upper shaft to aluminum frame. In addition to

the new airfoil design, a shaft design was also finalized. There will be two shafts used for the

wind turbine: a stationary (outermost) and rotary (innermost) shaft. The main support to hold the

weight of the airfoils and aluminum frame will be accomplished by the stationary shaft. On the

other hand, the rotary shaft will provide the rotations needed to produce the energy from the

movement of the airfoils around the shaft.

References

Wind Blue Power. DC – 540 Low Wind Permanent Magnet Alternator.

www.windbluepower.com. Copyright 2013. Retrieved November 20, 2013.