Objective:
Our objective is to design and model a device to water pump that
will administer water from a stream up a hill, with the following
requirements:
• Maximize the amount of water pumped in 1 minute at a head
of 6 inches
• Minimize resources and cost
• Generate electricity by wind or build a mechanical device
• Self-operating
• A maximum 3’x3’x2’ volume
Design:
Our team designed a turbine to generate electricity for the pump.
To keep the drag force low, we used 2mm thick PVC pipe with a
length of 0.254m. The base of the blades 3.8 cm and were cut at an
angle to 2cm. The edges of were sanded to help cut through the air
and the natural curvature of the pipe helps propel the turbine
around our circular hub, minimizing the drag. To produce more
power with fewer rotations we constructed a gearbox [shown
below] consisting of 2 parallel gear shaft and 4 gears resulting in a
1:11.11 ratio of rotation of the turbine to the rotation of the
generator.
Analysis & Testing:
When placed 1 foot in front of a perpendicular fan producing a
!
wind speed of 8.5( ! ) and 82.0 Watts, our turbine was able to
produce a voltage of 3.25 V and a current of 0.04 A. The input
power: Pin = V*A = 0.13 Watts. It was able to pump 0.4377 liters of
!"
!
!! !
(7.295𝐸
!
!
water at a flow rate of 7.295
). The efficiency of
the pump was 8.388% and the total cost of the device was $20.93
(including the pump and generator). Compared to the Betz’s limit,
the turbine was 50% less effective than the maximum possible
amount. (REUK.co.uk). However, the cost/efficiency is $249.52.
Overall it was very successful.
Conclusion:
In this experiment, we were able to successfully create a running
wind turbine. In doing this we were able to create enough power to
pump 14.8 ounces of water in one minute. We created our wind
turbine based of a full-scale wind turbine that has blades that are a
total of 116 feet, ours were 10 inches giving it a scale of 5/696 feet
(wind-watch.org). With this we can estimate that if our wind
turbine was full scale we would be able to create 452.4 volts at any
given time.
Some of the issues we ran into while building the wind turbine is
that before we had a bearing for the axle to spin in, the axle was
spinning so fast that it was burning the wood and causing the axle
to move down making the gears not line up. This was a huge
problem because when the gears weren’t meshing correctly, the
whole thing wouldn’t function properly. Another thing we found
was that if the gears weren’t lined up properly, there was way too
much friction making it near impossible for us to create enough
power to pump the water up 6 inches.
References:
Betz Limit
http://www.reuk.co.uk/betz-limit.htm
Turbine Dimensions
https://www.wind-watch.org/faq-size.php
Materials & Construction:
Material
Generator
Water Pump
PVC Pipe
Gears
Wood
Metal Rod
Total Cost
Cost
$6.00
$10.00
$1.70
$1.95
$0.28
$1.00
$20.93
When choosing what materials and how we wanted to build our
project, we thought about availability and durability of materials.
We used PVC pipe because it is widely available in our workshop
and because it is durable. While using PVC pipe we could make
any shape we wanted to by connecting the PVC pipe to multiple
joints making it really easy to make the shapes we wanted to. We
also used wood to support the stand. The wood acted as a durable
stand and was also very efficient product because of how cheap it
is.
The Village Project
Water Pump
Evan Wilmer, Jordan Lee, &Will Rooks
S4c/d