Portable Small-Scale Vertical Axis Wind Turbine with Pitch Angle Control System (H-Type VAWT)

International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395-0056
Volume: 10 Issue: 07 | July 2023 www.irjet.net p-ISSN: 2395-0072
© 2023, IRJET | Impact Factor value: 8.226 | ISO 9001:2008 Certified Journal | Page 228
Portable Small-Scale Vertical Axis Wind Turbine with Pitch Angle
Control System (H-Type VAWT)
Naguib Saleh1, Adel Kamal2, Ahmed Mahmoud3, Ali Moustafa4, Hedaya Farid5, Pola Osama6
1Doctor, Department of Mechanical Engineering, Canadian International College (CIC), Cairo, Egypt
2,3,4,5,6Students, Department of Mechanical Engineering, Canadian International College (CIC), Cairo, Egypt
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Abstract - This Researchpaperaimsto documenttheprocess
of designing & manufacturing a proof of concept of a portable
vertical axis wind turbine with A novel control method is also
demonstrated to offer exciting possibilities for improving
existing VAWTs. The idea behind the portable design is for the
user to be able to take the wind turbine to remote places that
lack electrical energy for long periods of time like refugee
camps & military barracks, the reason for using the pitch
angle control system is that by varying the pitch angle of the
blade this generates more lift force on it which corresponds to
a higher level of energy absorption and output power.
Key Words: Lift force, Portable, Vertical Axis, Wind
turbine, Darrieus vertical axis wind turbine (H-type
VAWT), Computational fluid dynamics (CFD), Variable
pitch angle control, Control, pitch angle.
1. INTRODUCTION
Energy resources can be divided into two types non-
renewable (oil, coal, and natural gas) and renewable (wind,
solar, geothermal, and hydropower) [1]. As non-renewable
energy resources are becoming scarce and expected to run
out shortly [2], therefore it is a fact that ways to obtain
energy from renewable resources must be developed to
satisfy the current and future needs of power consumption.
In this chapter; the types of non-renewable and renewable
energy will be discussed to understand the importance of
using renewable energy.
1.1 Non-Renewable Energy
Fossil fuels are generated from the preserved remains of
plants and animals and are found underground, as their
collective namesuggests.Fossil fuelsincludecoal,petroleum,
natural gas, oil shale, bitumens, tar sands, and heavy oils. All
of them contain carbon and are formed due to the geologic
process that acts on the remains of organic matter and this
process takes 300 to 400 million years to form naturally [3].
All fossil fuels can be burned in the air to produce Thermal
energy; this energy can then be used directly like in home
furnaces or can be used to heat water which in turn
produces steam which drives a turbine to generate
electricity, this process is called geothermal power
generation [4].
The applications mentioned are essential for a lot of
industries. However, fossil fuel combustion doesmoreharm
than good due to the large amounts of harmful emissions
such as CO2, Greenhouse gases & particulate Matter which
consequently affects not only the environment but also the
General well-being of the population [5]. According to the
Intergovernmental Panelon ClimateChange (IPCC)in2018,it
was calculated that 89% of global CO2 Emissions came from
fossil fuel combustion and that fossil fuel usage is the root
cause of global warming [6, 7].
Client Earth and IPCC warnthatfossil fuel consumptionmust
be halved in the next 11 years to avoid exceeding a global
temperature rise of 1.5°C, which would cause severe
consequences such as increased sea levels, extinction to
certain species of animals and crops, and extreme weather
[6, 7]. However, a report published by the United Nations
Climate Change reveals thatcurrent effortsareinsufficient to
prevent temperatures from rising above 1.5°C by the end of
2030, and the world may be on track for around 2.5°C of
warming by the end of the century. Luckily in the 1980s, the
familiar sustainable formsof energy werepresented(solar&
wind) [8].
This new approachtorenewableenergygenerationiscrucial
for our survival and as the International Renewable Energy
Agency (IRENA) Director-General Francesco La Camera said
“We are staring into a terrifying abyss of irreversibleclimate
consequences if we fail to act,” [9].
Moreover, Crude oil reserves are depleting at a rate of more
than 4 billion tons a year and at this rate, our known oil
reserves could run out in just over 53 years. If we increase
gas production to fill the energy gap left by oil, our known
gas reserves will also be used up within 52 years. And if
people try to accommodate for the decrease in the
production of oil and natural gas bycoal,theknownreserves
will be empty after nearly 150 years [2].
1.2 Renewable Energy
Renewable energy resources are the sources that naturally
renew themselves at a rate that makes them seem infinite.
There are many types of renewable sources of energy such
as (solar, wind, hydro, tidal, geothermal, and biomass) [10].

2.0 Mechanical Design
When determining the overall dimension of the project,
various factors were carefully considered to ensure the best
outcome. One of the most important considerations was
portability, as it needed to be easily transported from one
location to another. Additionally, the product was designed
to cater to smaller-scale operations, making it more
accessible to a wider range of users. User-friendliness was
also a key consideration, as the goal was to create a product
that was easy to use and navigate, even for those with
limited technical knowledge. All these factors werecarefully
weighed and balanced to create a final productthatwasboth
functional and user-friendly.
The portable wind turbine can be divided into two main
parts upper, and lower limps. Upper limps are the links,four
bar mechanism, servos, and blades. Lower limps are the
electronic housing, legs, and base which connects the lower
and upper parts.
2.1 Upper body of turbine
The blades have an airfoil NACA0018 profile with a chord
length of 190mm. Blades change their bitch angle using a
servo motor controlled by a microcontroller. Furthermore,
the links that hold the blades, are designed to contract and
extend using a four-bar mechanism. Designing such
mechanism needed to have a smooth transformation
between the mentioned two states which encouraged the
idea of using the four-bar mechanism withgearsasshown in
figure 1. However, a Complex mechanism dictates having a
part with complex geometry as a complementary. The most
complex piece geometrically is the servos’ holders, working
as an intermediate part between the servo and the blade
shown in figure2.
Figure 1: Four-bar mechanism and Gears.
Figure 2: Holder of blades
2.2 Lower body of turbine
The tripod acts as the base of the portable wind turbine,
providing the necessary support and stability. The main
objective of the design was to create a mechanically robust
structure that couldwithstandthedynamicforcesexertedby
the wind turbine. The placement of the legs at a 45-degree
angle from the base provided a stable and stable platform,
reducing the risk of slippage or excessive vibration during
work This arrangement these considerations are necessary
to maintain the design integrity of the wind turbine under
different wind conditions. First, the initial design of the
tripod featured three legs positioned at a 45-degree angle
from the base, ensuring stabilityandrigidityagainst external
forces. The tripod comprises three main parts: the base,
fixation plate, and legs, as depicted in Figures 3, 4, and 5,
respectively.
Figure 3: Base
The base is the intermediate part between rotatinglinksand
the legs. The Fixation plate is used to connect base and legs.
Finally, the legs are used to stabilize the wind turbine using
friction produced between legs ends and ground. In figure 4,
the tripod is able to shrink in size via moving legs towards
the center -closing- by pivoting around the fixation point in
the fixation plate. Furthermore, the legs are able to be
extended in case of the ground is not flat or had low friction
coefficient.
Figure 4: Fixation plate

Figure 5: Tripod closed Figure 6: Tripod fully extended
Figure 7: Final Design
3.0 Stress analysis
A stress analysis was conducted on the lower parts of the
wind turbine shown in the figure 8. The stress analysis was
done using a 100 kg using SolidWorks 2020. Results of this
simulation was conclusive that the geometry and material
selection of Aluminum was adequate and morethanenough.
Putting these findings as followed allows to draw a
conclusion that the Tri-pod is safe for commercial use.
Figure 8: Stress analysis on Tri-pod
4.0 Aerodynamics parameters associated with
Vertical Wind Turbine
Tip speed ratio (TSR) , a significantcharacteristic related
to VAWT blades, is calculated with using the following the
equation,
R is the rotor radius, the rotational speed of the rotor, and
wind velocity [12].
Figure 1: Forces and velocities acting on the blade of a
Darrieus turbine [12]
The forces acting on each blade can be used to predict the
actual VAWT performance. Figure 28 depicts the Vectors of
velocity and force acting on Darrieus turbine blades. The
tangential velocity vector of the rotor is represented by the
velocity . The relative velocity is represented by the
resultant velocity vector . which is composed of the
induced velocity (U) and blade velocity (V) vectors. The
angle of attack is typically defined as the angle formed
by the relative velocity direction, W, andthechordlineofthe

blade. The pitch angle of the blade is as specified in Ref. [13]
where is the angle formed by the directions and . The
angle of attack and relative wind speed (W), which is a
function of the azimuth angle ( ), obviously continuously
change during each cycle. As a result, the magnitude and
orientation of both the lift and drag forces vary with the
azimuthal position of the blade. The main forces acting on
VAWT blades are also depicted in Figure 28lift,drag,normal
(N), and tangential (T). The tangential force (T) [13] can be
used to estimate rotor performance. The power coefficient
(Cp) is the ratio of mechanical power generated by the wind
turbine (Pm) to wind power available (PW) [14].
where is the air density (1.225 kg/m3), and A is the area
swept by the turbine (e.g., for the H-type Darrieus wind
turbine, A = 2RH, where H is the blade length). However, for
VAWTs at low TSRs, a negative torque is often generated
because of the large dynamic cyclic variations in the angle of
attack (α).
5.0 COMPUTATIONAL FLUID DYNAMICS (CFD)
5.1 Introduction
Studying the characteristics of wind turbines was expensive
due to the use of wind tunnels. The rise of more powerful
computers had given researchers a new tool to study the
behavior of almost anysystemwhenincontactwithdynamic
fluid loads. Inexpensive and comprehensive as it is, this
method was favorable to be used for a graduation project.
The goal of studying wind turbine behavior is to determine
best way of increasing performance by using a control
system for pitch angle of each blade.
5.2 The CFD model
Ansys fluent was used because it has intuitive interface and
free license for students. Simulation was a 2-D three-bladed
H-Darrieus VAWT with NACA 0018 airfoil at different tip
speed ratios for both fixed and variable pitch angle
configurations. Sliding mesh technique was appropriate as
the desired measured outputs were variable in time which
required the use of a transient simulation.
5.3 Ansys Pre-process
CFD simulations with Ansys are not magically done. First
upload the required geometry. Second applya goodmesh on
top of it. Third tune the parameters of the simulation. All
explained in the following section.
A. Geometry:
The geometry is divided into multiple domains as follow:
1. Stationary domain: The dimensions need to large
enough to prevent a solid blockage effect of the
lateral boundaries Therefore, the dimensionsofthe
domain are 40 rotor diameters upstream (L1),100
rotor diameters downstream (L2), and 60 rotor
diameters width (W) [11].
Figure 10: Stationary Domain
2. Rotating domain: Usually it’s recommended to use
as small as it could be to better describe the
vorticity accurately and avoid undesirable
disturbances generated at the interface. The radius
was found to be approximately 2.95 of the rotor’s
radius.
FEATURE VALUE
ROTOR RADIUS (R) [MM] 656
BLADE HEIGHT (H) (2D)
[MM]
1000
BLADES NUMBER (𝑁B) [-] 3
BLADE PROFILE [-] NACA 0018
CHORD © [MM] 190
PITCH ANGLE (Β) [°] -6,-4,-0,4,6
AZIMUTH ANGLE (Θ) [°] 0 to 360
TIP SPEED RATIO (Λ OR
TSR) [-]
1, 1.7, 2, 2.7, 3.3

Figure 11: Rotating Domain
3. Blade sub-domain: Additional circular subdomains
are added to have a finer mesh around the airfoils.
Airfoils are hard to study because of its fast and
highly changeable pressure around it with every
step. The radius of the domain was approximately
1.6 the length of blades’ chord.
Figure 12: Sub-Domain
B. Generating mesh
Generating mesh is relatively hard process as it decides
complexity degree of solving the simulation. Although a
complex simulation to solve is desired for its accurate
results, the downside is the need of better technology and
patience, which means more money, to solve these hard
problems. The core problem is now clear, when generating
mesh, engineers should balance between accuracy and cost.
According to the literature [11}, the biggest two factors
affecting this kind of CFD is the value of Y+ and Courant-
Friedrichs-Lewy number (cfl) within a distanceof10mm far
from the blades and at the interface of rotating zone. The
element size on the interface of rotating zone has beenset to
39 mm.
Figure 13: whole Turbine after applying modificationonmesh
The solver is quite capable at capturing the pressure and
sheer stress in elements when it’s in the viscous sublayer or
fully turbulent sublayer. concluding to have elements close
to the wall to have Y+ close or under one [11] to ensure
accurate results. The blade was set to have 525 nodes on
edge and an inflation for 30 layers with first element
thickness of 1e-5 ensuring a Y+ under 1.
Figure 14: Blade after applying inflation on its edge
C. Fluent solver
ANSYS-Fluent uses many turbulence models based on
Reynolds-averaged Naiver–Stokes (RANS) equations to
represent the turbulent properties oftheflow.Thesemodels
typically include two additional transport equationsthat are
solved for the turbulence kinetic energy (k) and its
dissipation rate (ε or ω). The Shear-Stress Transport(SSTk-
w) model has been used when the literature was revised
[11].

5.4 Results:
Figure 15: Coffiencent of preformance of portable wind
turbine under normal operation.
6.0 Control:
In fixed angles lift is created by only 1 or 2 blades that are
meeting the wind flow at a better angle then slowed by a
breaking turbulence generated from the remaining blades
meeting the air at a worse angle. So, this makes other blades
suffer from mixed-up (vortex) air causing limited output
from available wind energy.
Therefore, variable pitch system shows lift from more than
two blades and less drag from others.Whichtranslatesintoa
higher level of wind energy absorption and output in the
form of power or mechanical drive energy solving the main
issue of vertical wind turbines making it self-starting.
First, The Anemometer that is placed beside portable wind
turbine measures Wind speed (V_W) and pass value to the
micro-controller. Then, The Incremental Encoder mounted
on the rotor shaft sends logical signals to micro-controller
for determining position and rotational velocity of rotor
shaft. The micro-controller uses previous mentioned values
to calculate Tip speed ratio (TSR). Select the best pitch angel
(𝛽) according to the best coefficient of performance C_P to
the current TSR at the end of the cycle each servo motor -
attached to each blade- will receive the suitable pitch angel
in respect of the blade’s position –Azimuth angel (𝜃). A
simple schematic figure 33 represents what was mentioned
up-close to further clarification.
Figure 16: Schematic of control
7.0 Cost Analysis
This analysis was carried out according to the Egyptian
prices in June 2023.
As startup company manufacturing 25 wind turbine per
month:
one-time fixed cost ( ):
Machines cost= (2 x 3d printer) + (1 x laser metal cutting
machine) + (1 x laser wood cutting machine) + (1 x arc
welding) = (2 x 20,000) + (1x15,000) + (1x120,000) +
(1x5,000) = 160,000 EGP
Fixed cost per month ( ):
Employee’s cost:
(2 workers x 3,000) + (1 Maintenance worker x 3,500) + (2
engineers x 8,000) + (10,000 renting cost) = 35,500
EGP/month.
Power consumption of the facility per month:
Electricity cost: (1000 Kwh/month) x (1.45 EGP/Kwh) =
1,450 EGP/month
Total fixed cost per month ( ) = (35,500) + (1,450) =
36,950 EGP
Variable cost:
Variable Cost per unit (v):
Material used for one wind turbine:
MDF wood (50) + Balsa Wood (1,100) + beech wood (100) +
bearings (240) + bolts and nuts (200) + Abs filaments
(5,000) + aluminum Links 3kg (1,500) + aluminum sheets
1kg (500) + aluminum pipes 8kg (5,000) + aluminum shaft
2kg (1,000) = 14,690 EGP
Electronics Components:
servo motors x3 (1,500) + wires (100) + Alternator(17,000)
+ 2 batteries (1,500) + slip ring (800)+ArduinoUNO(760)+
inverter (1,000) + Bluetooth modulex2(400)+breadboards
(50) + regulator (300) + anemometer (1,200) + encoder
(750) = 25360 EGP
Variable Cost per unit (v) = 14,690 + 25360 = 40,050 EGP
According to the revenue per unit (r) is 46,000 EGP
therefore:
Profit per unit = revenue per unit – variable cost per
unit= 46,000 – 40,050 = 5950 EGP
8.0 CONCLUSION
In conclusion, the findings from the real-time Internet of
Things (IoT) data and MATLAB analysis provide valuable
insights into the impact ofbladepitchingontheperformance
of wind turbines. The results demonstrate that employing
positive pitch angles can significantly enhance the power
coefficient at low Tip-Speed Ratio (TSR) of 1, resulting in an
approximate 4% increase in Cp.
By comparing the power coefficient values, which increased
from 0.03815712 to 0.041201, it is evident that the blade
pitching approach has a positive effect on the turbine's
performance. This improvement indicates that the wind
turbine's self-starting capabilities canbe enhanced,allowing

it to reach its nominal operating speed without the need for
additional power.
These findings have important implications for the field of
wind energy, as they suggest that optimizing blade pitching
can contribute to more efficient and cost-effective wind
turbine operations. By utilizing the blade pitchingapproach,
wind turbine systems can harness a higher proportionof the
available wind energy, maximizing power generation
potential.
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Portable Small-Scale Vertical Axis Wind Turbine with Pitch Angle Control System (H-Type VAWT)

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