UWE Bristol Engineering showcase 2015

Charlotte Alford
BEng Mechanical Engineering
Project Supervisor
Tushar Dhavale
Wind Turbine Design and Optimisation
Introduction
One of the main problems facing the world today is
energy consumption – where it comes from and the
effect obtaining this energy has on the atmosphere.
A great deal of work is being carried out with
renewable energy sources to maximise their use
and reduce the UK’s net carbon emissions. This
project takes this idea to a level where it can be
utilised by the general public: for charging devices
such as mobile phones in off-grid situations.
Section 1: Wind Data Analysis
Wind speed in the UK varies a considerable amount,
not only throughout the year but throughout the
day. It was found that the higher wind speeds
generally fall into the winter months when domestic
power consumption is higher. The mean wind
speed was found to be 2.53 m/s with the 99 th
percentile being 7.94 m/s. This range of wind
speeds was used for testing the optimisation model.
Section 2: Optimisation Model Testing
The optimisation model shown on the left was
used to vary the bucket chord length, bucket
overlap, number of stacks and the number of
blades. The end plates contained a series of
holes that the blades could be pushed into in
various positions. The whole device was fixed
to a permanent magnet axial generator which
allowed for power output analysis. These tests
also demonstrated strengths and flaws in the
model which were incorporated into the final
design.
Section 3: Position
A smoke stream was passed over a model of a
traditional Icelandic tent to demonstrate the
way the air travels around the tent. The
information from this test was used to
recommend possible locations which would
maximise the rotational speed of the turbine
and therefore power output. This was verified
using Ansys Fluent and the following positions
concluded.
Section 4: Final Design
The final design, when fully assembled will be
approximately 2.5m tall (subject to generator
size). This packs down so that all the blades
are stored within a single tube to which the
monopod sections may also be attached. This
tube, including end caps, measures just
0.5m x 0.15m – a size which is easily
transportable even in rucksacks.
Assembled Turbine
2.5 m
Packed Turbine
0.15m
0.5 m……
0.5m
To mount, the monopod has a spike at its based
which can be pushed into the ground by standing on
the foot pad. For stability, there is a plate below the
generator which has three holes for guy ropes to be
attached to. When these are pegged to the ground
in a triangular configuration, the model will be
secured against the oncoming wind. The brightness
of these guy ropes also serves as a safety feature.
The blades are made mainly from kite parts including
carbon and glass fibre poles, rip stop for the blade
itself and spar grabbers to join it together.
Key features of the final design include:
• The turbine packs down so that its components
are contained so they won’t be damaged or lost.
• The product lightweight for portability.
• The turbine can be assembled and disassembled
by one person.
• The turbine has features which maintain the users
safety including guy.
• The end plates of the model fold down to form
the end caps of the tube which contains all of the
blades and uprights rolled up.
Project summary
The project seeks to develop a design for a Savonius
Wind Turbine which is suitable for charging common
electronic devices in off-grid situations via USB
output. It is light weight and can be assembled and
disassembled by one person.
Project Objectives
• Research the use of wind power as an energy
resource and briefly compare it to other power
sources. Compare the different types of wind
turbine.
• Collect and analyse wind speed data to
demonstrate the range of wind speeds the final
product may experience along with the modal and
mean wind speeds.
• Using a subsonic wind tunnel, test the effect of
varying parameters including bucket overlap and
chord length, stacking and number of buckets.
• Model air flow over a tent using Ansys Fluent and
smoke stream testing in the wind tunnel, to
demonstrate the best position to achieve
maximum power output from the wind turbine.
• Use the information above to develop a design for
a light weight, portable wind turbine.
Project Conclusion
All of the objectives above were achieved and
resulted in a design which suitable for its function as
well as being aesthetically pleasing.
The next stage of this project would be building a
prototype and testing in the wind tunnel and
developing the design further in order to reduce
costs. It could also include developing the design so
it is suitable for a more permanent position, for
example on the roof of a house or industrial unit.