The Effect of Large Variation of Steering Angle on the Performance

of the Elliptical Savonius Wind Turbine

Agus Laka, Dedy Nataniel Ully, Bernadus Wuwur

and Bruno Liu

Department of Mechanical Engineering, State Politeknk of Kupang, Adi Sucipto, Kupang, Indonesia

Keywords: Kinetic Turbine, Steering, Rotor Blade, Performance, Wind Energy.

Abstract: There are still many villages in remote parts of Indonesia that have not enjoyed electricity from the State

Electricity Company due to various obstacles, namely the distance between people's houses which are far

apart, limited capacity of generating machines. For this reason, it is necessary to develop alternative energy

sources that can replace fossil-based energy sources with renewable energy such as water, wind, solar,

geothermal, biodiesel, bioethanol, biomass and other energies. The potential renewable energy source in

Indonesia is the use of wind energy as a wind power plant. This research was conducted with a real

experimental method with the aim of knowing the effect of large variations of the steering angle on the

performance of the elliptical Savonius wind turbine, so that it can be used as a reference for designing wind

power plants so that they can be applied to the community. The results showed that the guide with an angle

of 45

produced the highest power coefficient value of 0.41. Then followed by a guide with an angle of 55

which produces a power coefficient value of 0.32, while a guide with an angle of 65

produces a power

coefficient value of 0.18. The highest coefficient occurs at wind speeds of 4 and 5 m/s.

1 INTRODUCTION

There are still many villages in remote areas of East

Nusa Tenggara that have not enjoyed electricity from

the State Electricity Company due to various

obstacles, namely the limited economy of the

community in paying for electricity, large investment

costs due to the distance between people's houses

which are far apart, limited capacity of generating

machines, so they are unable to reach the area. rural

areas far from urban areas. In addition, the

geographical conditions of rural areas are

mountainous and difficult to access, making it

difficult to access the electricity network. Currently,

state power companies are still using Diesel power

plants and steam power plants to meet consumer

demand. However, electricity from the state

electricity company can only serve affordable urban

and rural areas, while remote areas are difficult to

reach.

Therefore, it is necessary to develop alternative

energy sources that can replace fossil-based energy

sources with renewable energy such as water energy,

wind, solar, geothermal, biodiesel, bioethanol,

biomass and other energies. The potential renewable

energy source in Indonesia is the use of wind energy

as a wind power plant. The kinetic energy of the wind

is captured by the blades with a certain area, thus

producing a rotational motion to rotate the turbine

rotor. The rotation of the turbine rotor is able to rotate

the generator shaft so that it will produce electrical

energy. Wind energy is able to replace the function of

fossil fuels as a source of power for electric

generators.

Research on the development of the Savonius

wind turbine has been carried out by many previous

researchers. Previous research was conducted in 2013

on the design of a vertical wind turbine of the

Savonius type with obstacle integration to obtain

maximum power. In this study, the obstacle was

integrated by providing a plate in front of the

returning blade with an angle of 80

,100

and a

semicircle. Based on the measurement results for the

integration of the obstacle with β=80

β =100

and

is in the form of a semi-circle. The results are

obtained if the integration of the semicircular obstacle

gets the highest power with a value of 0.00414 W

with RPM with 352 loading and without loading 354.

These results are much better than the power and

RPM produced by wind turbines without the use of

obstacles which only produce 0 power. 0019524 W

and RPM without loading 175.5 and with loading

Laka, A., Ully, D., Wuwur, B. and Liu, B.

The Effect of Large Variation of Steering Angle on the Performance of the Elliptical Savonius Wind Turbine.

DOI: 10.5220/0010938900003260

In Proceedings of the 4th International Conference on Applied Science and Technology on Engineering Science (iCAST-ES 2021), pages 11-16

ISBN: 978-989-758-615-6; ISSN: 2975-8246

 2023 by SCITEPRESS – Science and Technology Publications, Lda. Under CC license (CC BY-NC-ND 4.0)

162.9. This shows that the use of obstacles affects the

power generated by the Savonius type wind turbine

(Salby Cs, 2017).

Furthermore, research is conducted on the

analysis of wind flow on the Savonius type U wind

turbine blade based on software. In addition to the

experimental method by making a prototype of the U-

type Savonius wind turbine with 2 blades, a software-

based simulation method will be carried out to

analyze the air flow in the wind turbine blades. The

parameters that are varied only on the aspect ratio of

arc length and blade cross-section width, other

parameters follow previous research. This analysis

will be a comparison of data with the experimental

method. The simulation results are expected to get the

best blade aspect ratio (Ar) in capturing wind energy.

From the results of the study it was concluded that the

dimensions of the blades, both radius and cross-

sectional width greatly affect the air flow through the

turbine blades. Simulations without using a circular

sheild show that a blade with a radius of 65 mm and

a cross-sectional width of 100 mm is the best

variation based on the three airflow simulation

parameters. Simulations using circular sheild show

that the best blades and cross-sectional widths are R

75 and LP 100 (Candra Cs, 2018).

Further research was conducted on the efficiency

of the Savonius turbine prototype at low wind speeds.

This research was conducted on a small scale in the

field, namely on the beach to determine the highest

efficiency by using a prototype Savonius turbine at

low wind speeds. The results showed that the voltage

generated by the generator increased as the wind

speed increased. The Savonius wind turbine starts

rotating at a wind speed of 2.4 m/s. The average

efficiency of Savonius turbine for Y connected load

is 4.8% and for delta connected load is 14.5%

(Rudianto and Ahmadi, 2016).

Further research was conducted on the design of

the Savonius vertical axis turbine using 8 curved

blades. This research was conducted using

experimental methods in the field, with the aim of

knowing the magnitude of the power coefficient and

turbine efficiency. The results of the overall

calculation of the Savonius vertical wind turbine just

want to tell you how to design and build this wind

turbine. In this design, a Savonius turbine will be

produced which will produce 132 Watts of electricity

which can be used on a small scale such as a lamp at

home. While the coefficient of performance (Cp)

produced is 0.5275, the resulting tip speed ratio (λ )

is 0.372 and the turbine rotor efficiency is 0.5911

(Napitupulu and Siregar, 2013).

The next research was conducted on the design of

a two-level Savonius type wind turbine with a

capacity of 100 Watt for the Solo Syariah building.

The research was conducted using experimental

methods in the field with the aim of producing 100

Watts of electrical energy. The results show that the

wind turbine design has a power coefficient (Cp) of

0.18 and a tip speed ratio (λ) of 1. The aspect ratio (α)

and wind turbine overlap ratio are 2 and 0.2,

respectively. The turbine has 2 semicircular blades

and has a height (H) of 1.85 m and a rotor diameter

(D) of 0.92 m (Latif, 2013).

The last research is about the design of the

Savonius 200 Watt turbine. The research was

conducted using direct experimental methods in the

field. The results showed that the turbine rotates at a

speed of 54.2 revolutions per minute at a wind speed

of 2 m/s; 86.8 revolutions per minute at a wind speed

of 4 m/s; and 124.2 revolutions per minute at a wind

speed of 6 m/s. The results of the theoretical

calculation, the turbine will produce an actual power

of 17.51 Watt at V = 2 m/s; 140.05 Watts at V = 4

m/s; and 472.67 Watts at V = 6 m/s. The test results

and calculations show that the turbine will be able to

produce more than 200 Watts of electrical power at a

wind speed of 6 m/s (Rizkiyanto Cs, 2015).

2 RESEARCH METHODOLOGY

This research was conducted using a real

experimental method, namely making observations to

find causal data in a process through experimentation

so that it can determine the effect of large variations

of the steering angle on the performance of the

elliptical Savonius wind turbine where the same

treatment is carried out by varying the steering angle

on the performance of the wind turbine. Then

compare them, so that a pattern of interconnected

events is obtained.

The aim of this laboratory-scale research is to

improve the performance of the Savonius wind

turbine with a variation of the steering angle which

serves to reduce the negative torque on the rotor

blades, so as to improve the performance of the

Savonius wind turbine. The data collection process is

carried out by providing a load (kg) on the turbine

rotor, so that it can calculate the amount of torque,

power and power coefficient obtained by the elliptical

Savonius wind turbine. Data retrieval was carried out

repeatedly, namely 3 times, then the average value

was searched. The research instrument or installation

on the effect of large variations of the steering angle

iCAST-ES 2021 - International Conference on Applied Science and Technology on Engineering Science

on the performance of the elliptical Savonius wind

turbine can be seen in Figure 1 below:

Figure 1: Savonius. Wind turbine research instrument.

The blower will suck air through the wind tunnel, so

that the wind can flow at a certain speed and will hit

the rotor blades so that the turbine rotor can rotate

with a certain rotation according to the given wind

speed. Thus, there will be a change or conversion of

wind energy into motion energy in the form of

rotation of the Savonius turbine rotor shaft.

Furthermore, the rotation of the turbine rotor shaft

moves the loaded pulley to obtain the torque value

and will be used to determine the mechanical power

value of the turbine rotor. The rotation of the turbine

rotor and the given load will be measured in each

treatment according to the specified wind speed

variations, namely 3, 4, 5 and 6 m/s as well as

variations in the direction of the angle. The

dimensions of the turbine rotor blades are equipped

with guide angles as shown in the fig. 2 below:

Figure 2: Turbine rotor equipped with a guide with an angle

of 45.

2.1 Shaft Turn (n)

The Savonius wind turbine will rotate when there is

wind at a certain speed, so that the rotation of the shaft

produced by the Savonius turbine rotor can be

directly measured using a digital tachometer when the

rotor rotates.

2.2 Tip Speed Ratio (λ)

The tip speed ratio is the ratio of the speed at the end

of the rotor to the free air velocity. Tip speed ratio can

be calculated by the following formula :

.60







(1)

Where :

D : rotor diameter (m);

n : shaft rotation (rpm);

v : air flow velocity (m/s).

2.3 Power Wind

(

)

Wind power can be defined as the energy produced

per unit time as follows :



per unit time





(2)

.N m Joule

Watt

dtk dtk



Where :

power wind (Watt);



air mass density (kg/m

);

air flow velocity (m/s);

cross sectional area (m

2.4 Torque (T)

Torque is also known as moment or force which states

that an object rotates about an axis. Torque can also

be defined as a measure of the effectiveness of the

force in producing rotation or rotation around the

axis. The torque can be calculated using the formula:

T = F. r (N.m) (3)

F = (m-s) x g (N) (4)

Where :

T = torque (N.m);

` F =

force acting on the shaft (N);

m = loading mass

(kg);

s = spring balance(kg);

r = pulley radius (m);

g = gravity (m/s

)

The Effect of Large Variation of Steering Angle on the Performance of the Elliptical Savonius Wind Turbine

2.5 Power of Mechanical

Mechanical power is measured by loading the shaft to

get the torque value to calculate the angular speed.

Furthermore, the shaft power is obtained by

multiplying the torque value by the angular speed as

shown in the following equation:



xTP



(Watt) (5)

2 nxx







(rad/s) (6)

Where:



Power of mechanical (Watt);





The anguler velocity (rad/s);

n

Shaft rotation (rpm).

2.6 Coefficient of Power

The power coefficient is important in designing a

wind turbine because it shows how much wind kinetic

energy is converted into shaft power with the help of

the turbine rotor. The power coefficient is the ratio

between the energy used (input) and the energy

produced (output). The power coefficient formula is

as follows:

Cp 

(7)

Where :

Cp

Coefficient of power;



Power of mechanical (Watt);



Power of wind (Watt).

3 RESULT AND DISCUSSION

3.1 Result

Based on the test data in the field, data processing is

carried out for further analysis based on its tendency,

as shown in tables 1 and 2 below:

Table 1: The results of data processing on a guide with an

angle of 45

No Variable 3 m/s 4 m/s 5 m/s 6 m/s

1. Shaft Rot. 222.9 367.4 425.8 458.2

2. Tor

ue 0.008 0.018 0.030 0.037

3. Power wate

0.711 1.687 3.295 5.693

4. Power turbin 0.194 0.697 1.355 1.811

5. Coeff. powe

0.273 0.413 0.411 0.318

Table 2: The results of data processing on a guide with an

angle of 55

No Variable 3 m/s 4 m/s 5 m/s 6 m/s

1. Shaft Rot. 197.3 313.3 367.8 431.6

2. Torque 0.005 0.015 0.027 0.031

3. Power wate

0.711 1.687 3.295 5.693

4. Power turbin 0.121 0.514 1.076 1.407

5. Coeff.

owe

0.270 0.305 0.326 0.247

Table 3: The results of data processing on a guide with an

angle of 65

No Variable 3 m/s 4 m/s 5 m/s 6 m/s

1. Shaft Rot. 169.3 227.7 326.2 368.0

2. Torque 0.004 0.013 0.016 0.020

3. Power wate

0.711 1.687 3.295 5.693

4. Power turbin 0.073 0.315 0.561 0.793

5. Coeff.

owe

0.103 0.187 0.170 0.139

3.2 Discussion

After processing the data, it is displayed in graphical

form, so that it can be discussed based on the trends

shown in the graph. The discussion in question can be

seen in Figure 3, 4,5 and 6 below, namely:

Figure 3: The relationship between wind speed and shaft

rotation.

Based on the graph above, it can be seen that the

rotation (rpm) will increase linearly with the addition

of wind speed (m/s) on the three variations of the

guide angle. The magnitude of the increase in the

rotation value is determined by the wind speed

received by the rotor blades and also the

magnitude

of the existing guide angle. The 45

directional angle

has the highest rotation value of 458.20 rpm, followed

by the 55

directional angle of 431.60 rpm and the

directional angle of 368.03 rpm where

everything occurs at a maximum wind speed of 6 m/s.

The rotation value is also determined by the angular

speed (rad/s) and torque (N. m) generated by the wind

turbine.

iCAST-ES 2021 - International Conference on Applied Science and Technology on Engineering Science

Figure 4: The relationship between wind speed and torque.

Based on the graph above, it can be seen that the value

of torque (N.m) increases linearly with the addition of

wind speed (m/s) given to the three variations of the

existing guide angles. The magnitude of the increase

in the torque value is largely determined by the

amount of load received by the turbine rotor and also

the amount of wind speed received by the turbine

rotor blades. The greater the wind speed, the greater

the torque value produced. The 45

steering angle

produces the highest torque of 0.037 N.m, followed

by the 55

steering angle of 0.031 N.m and the 65

steering angle produces a torque of 0.020 N.m where

everything occurs at a maximum wind speed of 6 m/s.

Figure 5: The relationship between wind speed and

mechanical power.

Based on the graph above, it can be seen that the

mechanical power of the turbine increases

significantly at various variations in the number of

rotor blades with the addition of a given wind speed.

The magnitude of the increase in the value of the

mechanical power of the turbine is determined by the

torque, angular speed, rotation value and the

magnitude of the existing steering angle. The 45

steering angle can produce the maximum turbine

mechanical power of

1.81 Watt, followed by the 55

steering angle which is 1.40 Watt and the 65

steering angle produces the highest turbine

mechanical power of 0.79 Watt. The highest turbine

mechanical power occurs at a wind speed of 6 m/s

which is the highest given wind speed.

Figure 6: The relationship between wind speed and power

coefficient.

Based on the graph above, it can be seen that the

power coefficient increases parabolicly with the

addition of a given wind speed value. The magnitude

of the power coefficient is strongly influenced by the

value of rotation, angular speed, torque and power as

well as the existing steering angle. The guide angle of

produces the highest power coefficient value of

0.41 followed by the guiding angle of 55

produces

the highest power coefficient of 0.32 and the steering

angle of 65

produces the highest power coefficient

of 0.18. The highest efficiency in the variation of the

number of rotor blades occurs at a flow speed of 5

m/s.

4 CONCLUSIONS

Based on the results of the discussion above, several

conclusions can be drawn, including: the guiding

angle of 45

produces the highest power coefficient

value of 0.41 at a wind speed of 5 m/s. The guide

angle of 55

produces the highest power coefficient

value of 0.32 at a wind speed of 5 m/s.

The directional angle of 65

produces the highest

power coefficient value of 0.18 at a wind speed of 4

m/s.

ACKNOWLEDGEMENTS

On this occasion the author would like to thank all

those who have helped, so that the writing of this

scientific article can be completed properly, namely:

The Effect of Large Variation of Steering Angle on the Performance of the Elliptical Savonius Wind Turbine

 The leaders of the Kupang State Polytechnic who

have given the opportunity to participate in

research every year.

 Prof. Dr. Adrianus Amheka, ST., M.Eng, as the

head of the research and community service unit,

who has provided direction in conducting

research every year.

 ICAST 2021 colleagues and committee who have

provided guidance and direction in writing this

scientific article.

 Fellow researchers who have contributed to the

implementation of research and also the writing of

this scientific article.

REFERENCES

Candra, D., Harris, E., Fahmi, E. (2018). Analysis of Wind

Flow on the U Type Savonius Wind Turbine Blade

Based on Software. Journal of Applied Technology,

vol 04.

Latif, M. (2013). Efficiency of the Savonius Turbine

Protype at Low Wind Speeds. Journal of Electrical

Engineering, vol. 10, ISSN. 1412-4785.

Napitupulu, H., F., Siregar, S. (2013). Savonius Vertical Axis

Turbine Design. Dynamic journal, vol. 01, ISSN. 0216-7492.

Rudianto, D., T., Ahmadi, N. (2016). Design of 200 Watt Savonius

Turbine. National seminar on information technology and

aerospace, vol. 02, ISSN : 2528-1666.

Rizkiyanto, S., Chajana, D., P., Budiana, E., P. (2015). Design of

Two-Stage Savonius Type Wind Turbine With 100 Watt

Capacity For Solo Syariah Building. Journal of Mechanics,

vol. 14.

Salby, A., R., Nugroho, G., Musyafa, A. (2017). Savonius Type

Vertical Wind Turbine Design With Obstacle Integration To

Get Maximum Power. Journal of Engineering POMITS, vol.

01, pp 1-7.

iCAST-ES 2021 - International Conference on Applied Science and Technology on Engineering Science