6/23/2019
DESIGN AND
SIMULATION OF
A WIND
POWERED
ELECTRICITY
GENERATING
DEVICE FOR
ELECTRIC AND
HYBRID
VEHICLES
ABOKI: EN291-0656/2015 & SITWETI: EN2910664/2015
MECHANICAL
ENGINEERING DEPARTMENT
0
JOMO KENYATTA UNIVERSITY OF AGRICULTURE AND TECNOLOGY
Contents
DECLARATION ............................................................................................................................................... 3
ACKNOWLEDGEMENT ................................................................................................................................... 5
EXECUTIVE SUMMARY .................................................................................................................................. 5
LIST OF FIGURES ............................................................................................................................................ 6
LIST OF TABLES .............................................................................................................................................. 7
ABSTRACT...................................................................................................................................................... 8
INTRODUCTION ............................................................................................................................................. 9
PROBLEM STATEMENT.............................................................................................................................. 9
ADVANTAGES OF ELECTRIC VEHICLES................................................................................................. 11
CHALLENGES OF ELECTRIC VEHICLES. ................................................................................................. 11
OBJECTIVE ............................................................................................................................................... 11
OTHER OBJECTIVES ............................................................................................................................. 12
LITERATURE REVIEW ................................................................................................................................... 12
METHODOLOGY .......................................................................................................................................... 14
DESIGN. ................................................................................................................................................... 14
WIND TURBINE DESIGN ...................................................................................................................... 16
3D COMPUTER DESIGN. .......................................................................................................................... 19
TRIZ AIDED PROBLEM SOLVING TECHNIQUE .......................................................................................... 19
WIND TURBINE AERODYNAMICS ................................................................................................................ 20
BLADE DESIGN AND FABRICATION ......................................................................................................... 21
SHAPE OF WIND TURBINE BLADE. ...................................................................................................... 21
SIMULATION........................................................................................................................................ 21
DATA COLLECTION. ..................................................................................................................................... 22
DATA ANALYSIS. .......................................................................................................................................... 22
EXPECTED RESULTS ..................................................................................................................................... 23
BUDGET ....................................................................................................................................................... 24
WORK PLAN ................................................................................................................................................ 25
REFERENCES ................................................................................................................................................ 26
1
2
TITLE: DESIGN AND SIMULATION OF A WIND POWERED ELECTRICITY
GENERATING DEVICE FOR ELECTRIC AND HYBRID VEHICLES.
PRINCIPAL RESEARCHERS
NAME
SIGNATURE
1.
2.
SUPERVISORS
SIGNATURE
1.
2.
“Proposal submitted in partial fulfillment for the award of degree of Bachelor of science in
Mechanical Engineering”
DECLARATION
We………………………………………………………..and……………………………………
………………………..hereby do solemnly swear that the work presented in this document is
original and authentic and has never been presented before; to the best of our knowledge.
Researchers:
1……………………………………………………………………………….sign…………..
3
2………………………………………………………………………………..sign………
4
ACKNOWLEDGEMENT
We would wish to extend our sincerest gratitude to all our lecturers and fellow students for their
invaluable input and overwhelming support without which research presented in this proposal
would not have been possible. Notably, we would like to thank
……………………………………………..for the immense role he played in the supervision of
this project.
EXECUTIVE SUMMARY
5
LIST OF FIGURES
Fig 1.0………….
Fig 2.0………….
Fig 3.0…………
Fig 4.0…………
6
LIST OF TABLES
Table 1.0.………
Table 1.1………..
Table 1.2……….
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ABSTRACT
In most electric power generation applications mechanical energy is usually converted into
electric energy by use of generators. For wind powered systems, the kinetic energy of the wind is
harnessed by use of a turbine which rotates upon coming in contact with the wind; thus providing
mechanical energy. This energy according to the law of electromagnetic induction is then
converted into electric energy with aid of an electric generator. Rectifiers then convert the
resulting AC current into DC current which is then stored in batteries. When solid bodies move
through space they force the surrounding air currents to move at very high velocities. A wind
energy capturing device which includes a wind turbine is hereby designed to harness kinetic
energy from these high velocity air currents of the wind. It is then mounted on top of vehicles
such as trucks, vans and trains. This otherwise wasted wind energy is captured and directed to
the face area of the rotor blade thus rotating the turbine, which in turn, drives the generator to
generate electricity. The electrical energy may be stored in battery pack and used to drive the
motors of an electric vehicle or hybrid-electric vehicle. Most of electric vehicles today use a
combination of battery pack mounted on the chassis of the vehicle, an inverter and an electric
motor that powers the rear wheels. Although this is a cheaper way to power automobile vehicles,
most vehicles can only manage a limited range after which they will have to recharge. This is
costly in terms of time and money in case the vehicle was moving supplies. Our research aims to
solve this problem of recharging after every few miles by introducing this extra harnessed energy
to charge the batteries when the vehicle is moving. This will reduce the need to charge batteries
frequently.
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INTRODUCTION
PROBLEM STATEMENT
Since the invention of the IC engine vehicles, there has been rising concerns about the
alarming rates of air pollution and a global warming that culminates from combustion of
fossil fuels e.g petroleum. Fossil fuels such as coal and oil are being depleted as the years
go.
Table 1.0
Therefore, there is need to come up with innovative green energy solutions to power
modern vehicles, buildings and machinery. The rising demand for more energy around
the world compels us to seek additional sources of energy.
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Wind turbines are typically mounted on structural towers in areas known to have high
wind velocity. Various configurations of wind turbines are designed to convert the kinetic
energy of the wind into electrical power for use in homes and industries.
The greatest challenge with wind turbine as a reliable source of energy is that they
depend on the quantity and quality of the wind. Depending on the design, wind speed
must maintain a certain minimum velocity to overcome friction of moving parts. Even in
the best geographical areas, average wind speeds is only in the range of 18 to 45km/h.
typical rotor speed is between 20 and 50 rpm. To generate adequate power to return the
investment, sizes of wind turbines are very large, with rotor diameter range between 40 to
50m.
Fig. 1.0
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The rotor revolutions have to be stepped up though a gearbox to 1000 and 1500rpm
which is required for most types of electric generators.
Transport vehicles such as automobiles, trucks and trains are usually moving at moderate
to high speed on an open road. This movement generates an approximately opposite and
equal head wind speed relative to the vehicle. This wind causes “wind drag” and usually
lowers the fuel efficiency of the vehicle.
Due to air pollution and noise concerns, electric and/or hybrid electric vehicles are
gaining popularity around the world.
ADVANTAGES OF ELECTRIC VEHICLES.
 Low cost per kilometer of driving distance.

Reduced engine noise

Recovery of some energy through regenerative braking.
CHALLENGES OF ELECTRIC VEHICLES.
 Battery packs must be recharged when exhausted which takes some time.

Limited driving range due to limited storage capacity of the battery pack.
OBJECTIVE
To increase mileage in electric and hybrid vehicles through conversion of wind
drag into electric energy by use of wind turbines.
Wind powered electric and hybrid-electric vehicles will reduce pollution levels
and also reduce disease that are associated with air pollution such as cancer. Since
electricity is cheaper than gasoline or diesel, the driving experience will come at a
cheaper cost to citizens of most countries especially the developing ones such as
Kenya.
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OTHER OBJECTIVES
 Environmentally, this project provides a clean alternative source of energy to the
vehicles to fossil fuel based sources, which will reduce our environmental
footprint. By making use of a renewable and inexhaustible energy source, we will
be decreasing the energy related emissions.

Economically, designing and installing this device in electric vehicles, will be
able to subsidize the additional charging costs from the grid since it will reduce
the number of times needed to charge the vehicle from the main grid.

Politically, we are hoping that this can be a challenge to our country to use
alternative sources of energy that are cleaner and cheaper. This will go far into
making policies to support the same.

Ethically, this project aims to reduce and undo the vast damage we cause to our
environmental systems, by proving that renewable sources can be sustainable and
can serve us better that fossil fuel based sources.
LITERATURE REVIEW
For long time massive wind turbines have taken center stage as pertains to wind energy power
systems. Although wind energy is cheaper, inexhaustible and cleaner source of energy it has the
inherent problem of being unevenly distributed wind speed is also quite low even in areas
regarded as having high wind speeds. This has necessitated the use of huge turbines so as to
provide a significant amount of electricity. Consequently, initial installation costs of wind power
plants are quite high. This reason has discouraged the adoption of wind energy as a mainstream
source of energy.
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Currently electric cars have helped reduce the cost of road transportation but are limited in terms
of range owing to the low energy density of the battery pack when compared to gasoline or
diesel used in internal combustion engines. Most modern electric cars can only manage a limited
range of road travel before stopping and being recharged and thus wasting time. Various wind
turbine designs have been developed to aid in generating electricity for electric and hybridelectric vehicles. Most are bulky and contribute low efficiency of these vehicles. They may also
increase overall drag on the vehicle if not mounted properly. Our project involves designing a
compact device that overcomes, to a certain extent, some of the aforementioned limitations.
Wind turbines are majorly classified into two main types:
1. Horizontal axis wind turbines. (HAWTs)
2. Vertical axis wind turbines. (VAWTs)
The two configurations have instantly distinguishable rotor designs, each with its own favorable
characteristics. The vertical axis wind turbines can be classified into two major groups: those that
use aerodynamic drag to extract power from the wind and those that use lift. The advantage of
the VAWTs is that they can accept wind from any direction. This simplifies the design and
eliminates the problem imposed by gyroscopic forces on the rotor of a conventional machine as
the turbine tracks the wind. High rotor efficiency is desirable for increased wind energy and
should be maximized within the limits of affordable production. Energy carried by moving air is
expressed as sum of its kinetic energy.
1
𝐾𝐸 = 2 ⍴𝐴𝑉³
………………………………………………………………………………………………(1)
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Where V = air velocity.
A = turbine swept area.
⍴ = air density.
METHODOLOGY
DESIGN.
According to international regulations, there are no specific traffic law to regulate the installation
of wind power generation device for a vehicle. Therefore, the suggested design will be restricted
to the universal vehicle dimensions that are accepted by vehicle manufacturers. This is to ensure
that the design is compatible with the current electric vehicles in used i.e. trucks.
The limitations of the dimension of vehicles on the road is as listed below.
Table 1.1
RESTRICTION
Length
Not exceeding the length of overall vehicle
by 30%
Width
Not exceed the width of the vehicle
Height
The maximum height of the overall vehicle is
4m
Others
Should be connected with the main
construction of vehicle.
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Fig 2.0
roof of vehicle
rear of the vehicle
front of vehicle head
others
Fig 3.0
vertical axis type
horizontal axis type
This is after analyzing 24 patents filed on the wind power equipment for trucks or vehicles. The
analysis of installation location and type of wind power is shown above. Therefore, we are going
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to utilize the most effective location and type of wind turbine to be installed in a vehicle. That’s
installation at the roof and using a vertical axis wind turbine. The installation on the roof is such
that the device can directly get access to the speedy wind that is usually available at the roof of
the vehicle and reduce the energy lost by the car interior and airflow variation.
The use of the vertical axis wind turbine although it has a less efficiency as compared to the
horizontal axis wind turbine is stability of the turbine on the vehicle while in motion. Horizontal
axis wind turbine will also not be able to utilize the wind energy efficiently in this case.
WIND TURBINE DESIGN
We are going to design a wind turbine that will utilize drag to push the curved blades to generate
torque that will make the rotor turn. The Savonius wind turbine will be the best suited for this
case. Aerodynamically it’s the simplest wind turbine to design and build which reduces the its
cost drastically compared to the aero foil blade design of other VAWTs and HAWTs.
The working principles is very simple. The turbine rotates because of the difference of the drag
force acting on the concave and the convex parts of its blades.
fig 4.0
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The air is trapped in the concave part and pushes the turbine. The flow that hits the convex part
does produce a drag that is lower than the one on the concave part. It is the differential of the
drag force that causes this turbine to rotate.
This lowers the efficiency of the turbine as some of the wind’s power is used in pushing the
convex part and hence “wasted”. Our designed is going to be modified in a way such that only
one part will be exposed to the incoming air. This will increase the efficiency since there will be
no opposing drag on the other side. More blades will be added since will be dealing with wind
flowing at very high speeds as compared to a normal stationary wind turbine.
Fig 5.0
CHARACTERIZATION OF SAVONIUS WIND TURBINES
Every savonius wind turbine is characterized by the swept area As. this area influences the
energy output of the turbine, and the larger it is, the more energy the turbine collects.
𝐴 = 𝐻 ∗ 𝐷………………………………………………………………………(2)
Where H is height of the turbine.
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D is the diameter of the turbine.
The tip speed ratio of the rotor is defined by the equation
𝛾=
𝑉𝑟𝑜𝑡𝑜𝑟
𝑉
=
𝜔∗𝑑
𝑣
…………………………………………………………………………(3)
Where V is wind speed, ω is the angular velocity of the turbine, and d is the diameter of the semi
cylindrical blade.
The torque efficiency Ct is the ratio between the torque in the rotor and the theoretical torque that
the wind can cause.
𝑇
Ct =𝑇𝑤 = 1
4
𝑇
𝜌∗𝐴𝑠∗𝑑∗𝑉 2
………………………………………………………………………(4)
Where T is the torque in the rotor and 𝜌 is the air density.
The static torque coefficient Cts expresses the turbine ability to self-start. Its ratio of the
maximum static torque in the turbine and the theoretical wind torque
𝑇𝑠
Cts = 𝑇𝑤 = 1
4
𝑇𝑠
𝜌∗𝐻∗𝐷∗𝑉 2
………………………………………………………………………(5)
Where Ts is the maximum static torque.
The torque in the rotor can be calculated using the following equation T= I*α, where I is the
rotor’s moment of inertia and α is the rotor’s angular acceleration.
The power coefficient is the ratio of the extracted power from the wind to the available power in
𝑃𝑤
the wind: CP = 𝑃𝛼 = 1
2
𝑇∗𝜔
𝜌∗𝐻∗𝐷∗𝑉 3
……………………………………………………………(6)
Using these factors, we can learn the turbine’s characteristics and analyze its performance.
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3D COMPUTER DESIGN.
We are going to reverse engineer and borrow from the design knowledge of the existing
Savonius wind turbines using Autodesk Inventor software. Our design will be modified to
maximize on the efficiency and also a turbine that will provide minimum drag to the vehicle
while it is moving.
TRIZ AIDED PROBLEM SOLVING TECHNIQUE
Although a wind device on vehicle is able to utilize the renewable wind energy, it will cause the
vehicle air resistance increase, too. In order to solve the dilemma of air resistance rising and
pressure drag while the vehicle is moving, the TRIZ aided problem solving technique is
employed in this study. TRIZ theory is a theory that considers engineering problems suggested
solutions based on overcoming contradictions. The TRIZ matrix is a database of known solutions
able to overcome contradictions to solve contradictions. Using the known solutions in new
problems can bring innovative solutions. The procedure of the 40 TRIZ principle is shown
below. In this study, we adopt the TRIZ theory to assist identify the cause and effects of the wind
turbine blade design. When the problem occurs, the first step is to judge the problems which
belong to physical contradictions or technical contradictions. If there is no appropriate parameter
in the 39 characteristic parameter of contradiction matrix or 40 creative invention principles, the
technical contradiction can be changed into physical contradiction. Using the separation principle
to find out the essential components and features, and then seek for the method of problem
solving by analogy thinking.
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problems
contradiction
technical contradiction
physical contradiction
contradiction matrix
separation conflicts
(39*39 parameters) 40 principle
solution
WIND TURBINE AERODYNAMICS
The wind power system utilizes wind energy acting on the turbine to drive blades to drive the
generator for producing electricity. By Betz’s law, the maximum efficiency of wind power
converting of an ideal wind turbine is about 59.3% under the situation of no energy losing. This
is known as the “Betz’s limit”. However, in practical applications, the process of wind power
generation system from wind capturing to electricity converting needs to take the factor of the
loss of energy transfer of the component and devices into account. It includes many factors such
as mechanical transmission efficiency, generator efficiency and energy conversion efficiency.
The generated electricity is as in the equation below.
1
𝑃𝑤𝑝𝑠 = 2 𝜌𝐴𝑉 3 𝐶𝑃 ∗ 𝜂𝑇 𝜂𝐺 𝜂𝐸 …………………………………………………………………….(7)
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Where 𝑃𝑊𝑃𝑆 is the generating capacity of wind power generation system, 𝜌 is air density, A is
windward area, V is relative velocity of wind, CP is the power conversion coefficient, 𝜂𝑇 𝜂𝐺 𝜂𝐸 is
the efficiency of mechanical transmission, generator efficiency and power conversion efficiency.
BLADE DESIGN AND FABRICATION
SHAPE OF WIND TURBINE BLADE.
In the wind turbine blade could increase air resistance and pressure drag problems. The turbine
blade design needs to balance this cause and effect. In other word, is should overcome the
contradictions carefully. Thus after we find out the 40 inventions principles in contradiction
matrix of TRIZ theory, we adopt the most appropriate solution method to set the shape of the
blades.
SIMULATION.
The goal of this project is to check the amount of power the device can be able to generate in the
moving vehicle and by how much it can assist to increase the range of the vehicle. To test the
performance of this device we are going to import the CAD geometry to a computational fluid
dynamic software (ANSYS) which is going to solve the fluid dynamic equations around the
geometry following constraints we specify. In order to determine the point at which these
equations will be solved a mesh is generated. The mesh discretizes the physical space into finite
number of points. The higher the quality of the mesh, the accurate the solution and the more time
and power it will take to solve.
After we get a quality mesh we are going to specify our set up in fluent. From this stage we will
be able to collect the data that we require after making the required boundary conditions for the
set up.
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DATA COLLECTION.
The data that will are going to collect will come from the simulation of the design in the
computational fluid dynamics software.
We are also going to perform experimental tests of the fabricated device and record its
performance parameters.
DATA ANALYSIS.
The data collected will be analyzed to check whether the amount of power the device can
generate is substantial to give the vehicle additional mileage.
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EXPECTED RESULTS
It is expected that this wind powered generating device will generate sufficient additional
electrical power for trucks. Consequently, this will reduce over reliance on fossil fuels such
as diesel which is commonly used to power the internal combustion engines of such trucks.
As the batteries used in these trucks will self-charge while the truck is in motion we do hope
that over reliance on the grid, when battery packs are recharged at designated charging
stations, will also reduce; should this device be adopted by industry as a mainstream source
of power.
On overall, the cost of transporting goods from point A to point B is also expected to drop
drastically thus making it cheaper for most companies to do business.
From an environmental conservation standpoint, reducing consumption of fossil fuels will go
a long way in helping the environment recover from years of pollution.
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BUDGET
Table 1.2
ITEM NO
QUANTITY UNIT COST
TOTAL COST
1.Turbine
blades
2.Generator
3.Battery
pack
4.Casing
GRAND TOTAL
Kshs. 10,000
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WORK PLAN
Table 1.3
The proposed work is approximated to last a period of eight months. The figure below is an
overview of how the planned activities will take place.
MONTHS
NO. DESCRIPTION JUN JUL AUG
1
2
3
SEPT
OCT
Preparation of
the project
proposal
First
presentation of
the proposal
Design and
simulation
Second
presentation
4
5
6
Testing of
experimental
model
Final
presentation
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NOV DEC JAN
FEB
MAR APR MAY JUN
REFERENCES
1. G. J. Herbert, S Iniyan, E. Sreevalsan, and S. Rajapandian, “A review of wind energy
technologies,” Renewable and sustainable Energy Reviews, vol. 11, no. 6, pp. 1117-1145, 2007.
2. M. Ragheb, “wind turbines theory – the Betz Equation and Optimal Rotor Tip Speed Ratio”.
[online]. Available: http://cdn.intechopen.com/pdfs-wm/16242.pdf. [Accessed: 29-Jan-2017].
3. U.K Saha, and M Jaya Rajkumar,2006, “On the Performance Analysis of Savonius Rotor with
Twisted Blades,” Renewable Energy vol. 31,1776-1788.
4. Auto Energy website, The wind Deflector on Truck Toward the Effect of Drag and Fuel
consumption” http://auto.itri.org.tw/research/DOC/mem5_2_3.pdf.
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