DOI : 10.17577/IJERTV7IS010116
- Open Access
- Total Downloads : 233
- Authors : Sonali Mitra , Abhineet Singh , Pragyan Jain , S. V. H. Nagendra
- Paper ID : IJERTV7IS010116
- Volume & Issue : Volume 07, Issue 01 (January 2018)
- DOI : http://dx.doi.org/10.17577/IJERTV7IS010116
- Published (First Online): 22-01-2018
- ISSN (Online) : 2278-0181
- Publisher Name : IJERT
- License:
This work is licensed under a Creative Commons Attribution 4.0 International License
Designing of Vertical Axis Wind Turbines for Low Speed, Low Altitude Regions of Central India
Sonali Mitra Graduate Engineer Trainee EM Services (I) Pvt. Ltd
Abhineet Singh Department of Materials Imperial College London
Pragyan Jain
Department of Mechanical Engineering Gyan Ganga Institute of Technology and Sciences
S.V. H. Nagendra
Department of Mechanical Engineering Gyan Ganga Institute of Technology and Sciences
Abstract A Straight Blade type, Vertical Axis Wind Turbine was designed having an output of 2.5 kW for the installation in the college campus of Gyan Ganga Institute of Technology and Sciences, Jabalpur. Advance methods of additive manufacture technology like Fused Deposition Modelling type 3D Printing is used for making a model and experiment is conducted.
Keywords VAWT, 3D Printing, Airfoil S2027, CFD, Drag Force.
-
INTRODUCTION
In an era, where energy is a strategic need for development and growth, energy supply is running behind energy demand. In order to make sure there is substantial development, we must consider all possible sources to fulfil our energy requirement, especially now, when we are running short on our major source of energy, i.e. fossil fuels (coal, petroleum etc.). Fossil fuels have been the main source for energy production for decades, and they are now depleting. Also, they are a major cause of pollution, which gives rise to problems like global warming. Thus, to maintain the economic growth and to save the planet at the same time, no options seems more favourable than renewable energy sources like solar, wind etc. Renewable sources not only provide energy which has negligible to zero carbon emission, but is in abundance, with a promise of never ending.
Amongst the many source of energy, wind energy seems to be a promise-able source as its non – polluting and a continuous source of energy. Wind Energy seems to a favourable option that can be considered as there is a continuous flow of wind throughout the year and round the clock. In any wind power system, the main efficiency of the system depends up to the design of the blade which mainly depends on the factors like Airfoil Shape, Wind Speed, Blade Dimensions, Blade Material etc.
All the three profiles are selected for the further development of a Vertical Axis Wind Turbine.
Figure 1. -1- Vertical Axis Wind Turbine`s Rotor
-
SITE SELECTION
The work for site selection was done by the Pragyan Jain et al [1]. Selection of site was done using CFD Simulation on ANSYS Fluent, where the Bluff Body of the Gyan Ganga Institute of Technology and Sciences, Jabalpur, was made with the help of Google Earth and CAD Modelling. The results so obtained were taken as the base for designing the VAWT system where average wind speed, was approximately 1 m/s or 3.6 km/hr. Also, the data given by Metrological Department also states that average wind speed in Jabalpur regions is around 0.972 m/s or 3.5 km/hr.
Figure 2.1- Wind Patterns by Google Earth
The most potential zone found for VAWT`s installation was between the two-college building of Gyan Ganga Institute of Technology and Sciences and Gyan Ganga College of
Technology, roughly at a height between 20 100 feet from ground level [1].
-
Force Calculation
Drag Force is calculated using the following [3] formula.
0
2
= 2
Torque provided by one single blade of VAWT [3] is given by
= x R
Total torque by VAWT is given by
= x T
Figure 2.2 – Location and Coordinates of GGITS
-
Calculation for Selection of Generator
For selecting an effective generator, rotor speed and number of poles of generator is an important parameter, which can be calculated from the following formulas, respectively.
P = 2 N T
60
-
-
CALCULATIONS FOR DESIGNING
Following are the steps taken to design the VAWT.
and
P* = 120 f
N
3.1 Airfoil Selection
Experiment was conducted on Sub Sonic Wind Tunnel setup using three airfoil profiles, namely NACA 0012, NACA 0015
where f in India is 50 Hz.
3.6 Results of above calculations
The following results were obtained from the calculations-
and S2027. The results were then verified using CFD
simulation using ANSYS CFX and hence, it was concluded
– 2.5 m
that S2027 has higher capability of generating Drag Force [2]. Also, the same was reported by the T. Letcher [3], that with the use of S2027, there is an increase in overall energy
– 0.5 m
– 0.0723771 m
Assuming the following values for further calculations-
production by 16%.
0
– 4.0 m/s
-
Power Calculation
The designing of VAWT was done with an expectation of 2.5 kW power output. The following formula [4] was used for calculating the area of blade keeping the known quantities in consideration.
– 1
– 2.3 m
Other useful results from the calculation are as follows.
– 11.700
N
1
– 27.071
N m
5
– 135.355
N m
N
– 176.464
rpm
P
– 34.001176
Poles
P = 1 3
2 A v0 Cp
-
Calculation for Dimensions
With the use of Aspect Ratio (AR) [4], it was easy to calculate the dimensions of the blade of the VAWT.
AR =
With the use of Solidity [4], the number of blades was calculated.
=
-
-
COMPUTER AIDED DESIGNING
-
CAD Modelling
Complete CAD modelling, simulation and rendering of the VAWT was done using Autodesk`s Fusion 360. Figure 5-1 shows complete assembly of Final CAD model of the VAWT, while Figure 6-1 and 6-2 shows the CAD model`s exploded view of both the rotor and stator respectively.
Figure 4.1 CAD Model of VAWT
-
STL File Generation and 3D Printing
CAD files of the selective parts which were to be 3D printed were saved as STL files and were opened on the CURA, slicing software where final G-Code was written which was later fed to the 3D Printer. Layer height was maintained as 0.2 mm for all 3D Printed parts and all the parts were printed at nozzle temperature of 210 , without the bed heating. 3D Printing was done on Prusa i3 3D Printer using FDM process with Poly-Lactic-Acid (PLA) as the printing material having
1.75 mm diameter. Blades were printed with a wall thickness of 2 mm and had 75% infill, which enabled us to gain strength and reduce weight at the same time. Figure 5-2 shows the sliced CAD model of blade in CURA.
Figure 4.2- STL File Slicing in CURA
Figure 4.3- Blade being printed on Prusa i3
-
-
MODEL MANUFACTURING
Following steps were taken in the manufacturing process.
Figure 4.4 – Final Model
Figure 4.5 – Final Model
-
Rotor Manufacturing
Total of 5 blades having S2027 profile were 3D Printed. Two hubs having top and bottom airfoil holders having a freedom of 360 such that Angle of Attack can be changed. A Nut and Bolt system was provided for the same. Provision for Aluminium Flange Coupling was also made within the hub such that the Stainless Steel, Solid Shaft having a 10 mm diameter can be easily held inside it.
Figure 5.1- Exploded CAD View of Rotor
-
Stator Manufacturing
Wooden base, having a Mild Steel frame was made for holding both the Rotor, Generator and other electronics. The rotor rested on a JP 51100 Thrust Bearing. Upper end of the rotor was held by a NBC 6000Z Deep Groove type Ball Bearing and the bottom end was coupled to a DC Motor via Flange Coupling. A DC Motor (12 V) having 1000 RPM was geared down to 200 RPM and was further used as a Generator.
Figure 5.2 – Exploded CAD View of Stator
-
-
TESTING AND RESULTS
The model of the VAWT was tested in a frugal setup, in which an Air Blower was used as Wind source. The air blower had a rated discharge of 3.3 m3/min. The air blower was kept at a distance of 1 foot (304.88 mm) from the tip of the blade. Variations in blower speeds were changed using the blower pre-sets. The outlet of the air blower was positioned in such a way that it came approximately in the centre of the blades. Vibration damping was done using a dead weight (Brick) for the model. A hand held digital Tachometer was used to find the rotor speed at various wind speeds. A digital Multi-Meter was clipped on both the terminals of the Generator. In case of No-Load Condition, Voltage was taken whereas when an LED was connected, both Current and Voltage was measured. Resistance across the LED was taken using a multi-meter.
-
No Load Condition
Following Table 1 shows the results obtained in No Load condition.
7.00
6.00
5.00
4.00
3.00
2.00
1.00
0.00
Rotor Speed (RPM) Vs Voltage (Volts)
5.76
4.75
3
.74
4.39
1.8
2
.79
0.79
0 200 400 600
Rotor Speed (RPM)
Figure 6.1- Testing with No Load
Graph 3 – Rotor Speed vs Voltage
-
Loaded Condition
We know that
Table 1- Readings in No Load Condition
P = V I cos
No Load Condition
Speed
Setting
Wind Speed
(m/s)
Rotor Speed
(RPM)
Voltage
(V)
1
6.89
57.00
0.79
2
13.78
77.00
1.8
3
20.68
198.00
2.79
4
27.57
218.00
3.74
5
34.46
340.00
4.39
6
41.35
419.00
4.75
7
48.24
478.00
5.76
Since its DC Current cos = 1.00 Resistance across LED`s = 4.00
Thus, we can calculate the current flowing through the load (LED).
600
500
400
300
200
100
0
Wind Speed (m/s) Vs Rotor Speed (RPM)
478
4
340
19
1
98 218
57 77
0 20 40 60
Wind Speed (m/s)
Graph 2- Wind Speed vs Rotor Speed
Figure 6.2 – Testing with Load
Loaded Condition
Speed Setting
Wind Speed
(m/s)
Rotor Speed
(RPM)
Voltage
(V)
Current
(A)
Power
(W)
1
6.89
57.00
1.26
0.32
0.40
2
13.78
124.00
1.84
0.46
0.85
3
20.68
145.00
1.99
0.50
0.99
4
27.57
252.00
2.2
0.55
1.21
5
34.46
276.00
2.32
0.58
1.35
6
41.35
279.00
2.45
0.61
1.50
7
48.24
313.00
2.64
0.66
1.74
Table 2- Readings in Loaded Condition
350
300
250
200
150
100
50
0
3.00
2.50
Wind Speed (m/s) Vs Rotor Speed (RPM)
276 2
79
252
1
124
45
57
313
0 20 40 60
Wind Speed m/s
Graph 3 Wind Speed vs Rotor Speed
Rotor Speed (RPM) Vs Voltage (Volts)
8. FUTURE SCOPE
A full scale Straight Blade type, Vertical Axis Wind Turbine designed for 2.5 kW can be installed in the college premises. Its application would become a stepping stone in promotion of Green Energy, which shall benefit both the environment and institute for coming future.
List of Symbols
A = Cross Sectional Area swept by Wind c = Chord Length
= Coefficient of Drag
= Coefficient of Lift
= Coefficient of Power
= Maximum Cp
f = Frequency of Current
N = Rotor RPM
2.00
= Number of Blades
1.50
1.00
0.50
0.00
2.00
2
2.4
2.2
.64
5
1.99
1.84
1.26
2.3
2
0 100 200 300 400
Rotor Speed (RPM)
Graph 4- Rotor Speed vs Voltage
Wind Speed (m/s) Vs Power (Watt)
P = Power Produced (Output)
P* = Number of Poles in Generator R = Radius of Rotor
Re = Reynold`s Number
0 = Velocity of Air
= Angle of Attack
= that maximises Cp
= Density
= Solidity
1.50
1.00
= that maximises Cp
REFERENCES
0.50
0.00
1
1.35
1.7
.50
4
0.
0.85
1.21
99
0.40
0 10 20 30 40 50 60
Wind Speed (m/s)
Graph 5 – Wind Speed vs Power
-
-
CONCLUSIONS
-
Jain Pragyan, Malvika Pateria. Optimization And Site Selection For Installation Of Low Speed Wind Turbine In Central India. International Journal Of Innovation In Engieering Research & Management. ISSN: 2348-4918.
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Singh Abhineet, Mitra Sonali, Nagendra S.V.H And Jain Pragyan. Selection Of Airfoils For Vertical Axis Wind Turbines For Low Speed, Low Altitude Regions Of Central India. International Journals Of Advanced Research In Computer Science And Software Engineering. ISSN: 2277-128X (Volume-7, Issue-11).
-
T. Letcher. Small Scale Wind Turbine Optimization For Low Wind Speeds. The Ohio State University, Columbus, Ohio.
-
S. Brusca , R. Lanzafame And M. Messina. Design Of Vertical Axis Wind Turbine How The Aspect Ratio Affects The Turbine`S
As per the theoretical design and experiment performed on the scaled down model, a Straight Blade Type, Vertical Axis Wind Turbine having an airfoil shape of S2027, will be proved useful in the Central India region, averagely having Low Wind Speed.
Performance. International Journal Of Energy Environment Engineering (2014) 5:333340