WIND –2– H2OMECH 4020: Design II

Group 12: Jeffrey Allen Daniel Barker

Andrew Hildebrand Tom McDonald

Supervised by: Dr. Alex Kalamkarov Client: Dr. Graham Gagnon

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Presentation Agenda

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• Background

• Design Overview

• Design Modifications

• Testing

• Budget

• Design Requirements

Design CompetitionProject inspired by theme of 2008 Design Competition

posed by WERC: A Consortium for Environmental Education and Technology Development

Competition held at New Mexico State UniversityApril 5th – 8th

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Competition Design ChallengeDesign a device that uses wind power

to directly power the filtration of brackish water

i.e. no generation of electricity

Interdisciplinary Collaboration

Working with a team of two CivilEngineering students: Matt Follett

Dannica Switzer

Responsible for water treatment system

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December 2008 Design

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January 2009 Update

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Completed Windmill

Design Overview

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Design Overview - Blades

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• Clockwise rotation • Blade tip deflection• Light weight (Al 5052-H32)• Safety factor of at least 10

for centrifugal forces• Optimize performance for

low winds (3-6 m/s)• Solidity ratio of 80%• 10 degree averaged angle

of attack

Design Overview – Blade Attachment

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Design Overview - Hub

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Design Overview - Gearbox

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Design Overview - Gearbox

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• 1” diameter shafts• 1010 steel for rotor shaft,

4140 steel for geared shafts

• Maintain a safety factor of at least 5 (keyways, variable loads)

• Stress analysis - torsion, bending, buckling,

• Vibration – critical speed• Deflection – spacing

between bearings

Design Overview - Gearbox

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• System meets or exceeds ANSI B29-1 - Precision Power Transmission Roller Chains, Attachments, and Sprockets

Size Pitch, in. Roller diameter, in. Ultimate strength, lb. Working load, lb.

40 0.500" 0.312” 3,125 810

60 0.750" 0.469" 7,030 1,980

Design Overview – Crank Mechanism

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• 3 inch stroke length

• Brass bushings used to allow for relative motion between shaft and crank arm

• Cotter pins prevent crank arms from slipping off ends

Design Overview – Pump Block

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• Crank arm drives pump block up and down

• No relative motion between vertical shafts and pump block due to split pin (better for seal)

• Two ½” shafts constrain lateral motion through two brass sleeve bearings

Design Overview – Yaw Bearing

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• Lazy susan bearing rated for 1000 lbs. used to yaw the nacelle

Design Overview – Pump

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• Brass pipe with two check valves

• Leather seals provide seal between valves and pump wall

Design Overview – Stand

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• Stand inherited from Vertical Axis Wind Turbine 2005/2006

Design Overview – Overspeed Protection

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• Furling at 11 m/s

• Thrust force on blades

• Force on Tail

• Offset angles

Design Modifications

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Design Iteration – Flange Thrust Bearing

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THRUST BEARING • Added to stop pump rod from

unthreading itself during yaw motion• Transmits tension and compression along

pump rod, while providing zero torque• Consists of a rigid flanged housing

welded to the upper pump rod with two sets of tapered roller bearings press fit into it

• Lower pump rod locates onto roller bearings via a welded collar and tensioning nut

Design Iteration – Brass Pressure Seal Cap

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Design Considerations

SEAL CAP• Added to provide a pressure seal at

interface of pump rod and pump• Consists of a brass cap with pipe

threading that has seated in it a rubber wiper to prevent dirt from entering the pump, and a rubber seal

Design Iteration – Stainless Steal Pump Rod

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Design Considerations

STAINLESS STEEL PUMP ROD• Originally made of steel, which was

rusting• Replaced with a stainless steel pump rod

to resist corrosion

Testing/Results

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Testing• Test #1: Point Pleasant Park

– Unstable back pressure (butterfly valve)– Wind speed ~4 m/s– Proof of concept test– No data recorded

Testing• Test #2: Dalhousie Wind Tunnel Lab

– Air flow: 42” box fan– Wind speed ~4.5 m/s– Filters couldn’t handle high flow rate– Unstable back pressure (butterfly valve)– Civil students were able to reduce particulate in

sample from >6000 ppm to <150ppm97.5% particulate removed!

Testing

Testing• Test #3: Lawrencetown Beach

– Wind speed ~ 5.5 m/s gusting to 9 m/s– 75 psi pressure relief valve generates back

pressure– Wind speed taken every 5 seconds– Volume water taken every minute– Wind speed nearly constant over rotor face

Results

• Average back pressure taken as 80 psi• Able to determine efficiency based on theoretical kinetic energy of wind flux

Testing

• Optimum efficiency occurred near 4.7 m/s

Testing

• RPM optimized (steepest slope) around 5.3 m/s• RPM is concave down above 5.3 m/s

Testing

• Turbine performed better than anticipated• Flow rates approximately 50% higher than expected

Testing• Test #4: Wind Tunnel Lab

– Three wind speeds (low, medium, high)– 30 psi relief valve added– Flow rates recorded at 0, 35, and 75 psi– Volume water taken every two minutes– Air flow highly complex, uneven over rotor face– Analogous wind speed undeterminable

Testing

• Curve becomes more linear as wind speed increases• Demonstrates higher flow rates at higher wind speeds

Safety - Hierarchy of Control

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Budget

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Budget

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Item Cost

Hub/Blades $ 70.00 Gearbox $ 570.00 Pump System $ 590.00 Tower $ - Tail/Furling System $ 250.00 Miscellaneous $ 320.00 Testing $ 190.00

Total $ 1,990.00

Design Requirements

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Design Requirements

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Design Requirement Met Include an over-speed control system for the turbine

to avoid catastrophic failure and ensure public safety.

YES?

Be designed for constant operation in remote areas YES Utilize pump components suitable for continuous

contact with brackish groundwater. YES

Maximize flow rate to provide the most drinking water with the least amount of wind energy. YES

Contain little to no electronic components. YES

Design Requirements

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Design Requirement Met

Be constructed of locally available and off the shelf materials. NO

Consider social implications of a wind pump installed in a remote, poor community. YES

Be able to respond to the intermittent nature of wind without interruption to the normal function of the system, i.e. no re-priming of the pump.

YES

Require minimal human attention except for construction of the unit and regular maintenance YES

Design Requirements

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Design Requirement Met

Pump water from a suitable brackish water table depth. This is the average water table depth in geographic location to be determined.

YES

Pump as much water as possible at a minimum wind speed in the range of 3-6 m/s, with the objective of being usable in remote areas with low to medium wind resource.

YES

Produce the minimum fluid pressure required for the filtration of brackish water. The design water pressure set by the civil engineering team is a minimum of 517 kPa (75 psi).

YES

Acknowledgements

Dr. Joshua Leon Dr. Graham Gagnon Dr. Alexander Kalamkarov

Dr. Julio Militzer48

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