Abstract— INTRODUCTION In today’s world the need

Abstract— The turbine is specially constructed so as to mimic the bio-mechanics of birds’ wings in order to develop electricity. It consists
of flapping blades which are connected via a mechanism to a motor. The turbine is also equipped with solar cells in order to add to the
electricity generated and also to help generate electricity when wind velocity is low. This project was initiated keeping in mind the fact that
the large dimensions of current turbines occupy large space and thus have reduced application in urban areas. This project aims to make
the current turbine design compact and aims to utilize a new design for wind energy generation.
Index Terms— Drag, Flapping, Wind, Wing, Solar, Turbine
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1 INTRODUCTION
In today’s world the need for renewable resources is on the
rise as the availability of conventional resources like petroleum
and coal reduces. Although wind energy has been utilized
since ages the current design of the wind turbines requires a
lot of space and the large rotating blades pose a threat to the
bird population in areas where they are installed. Also these
turbines are dependent purely on air flow as their primary
source of energy thus making the current design less efficient.
Another drawback of current designs is that the density of
such turbines is very limited as they cannot be installed very
close to each other thus affecting net power output per sq.m
area.
The project aims to use the combination of wind as well as
solar energy to generate electricity .The flapping wing design
(similar to that observed in birds during flight) helps to make
the wind turbine compact. The flapping wings motion is then
converted into rotary motion to generate electricity. Additionally
by mounting solar panels on the outer periphery of the
central hub helps add to the electricity generated thus improving
the energy output per turbine.
2 DESCRIPTION
The wind turbine design is particularly inspired by the flapping
motion of a humming bird. The path traced by the humming
bird’s wing during hovering follows the shape of an infinite
loop. This path is ideal for flapping as the amount of
vibrations transmitted to the supporting structure are the least
thus giving more stability to the entire structure. The mechanism
developed for the wind turbine is tuned to trace the infinite
path so that the flapping occurs in a similar manner to
that of a humming bird.
Ideally the power output can be maximized if the entire wing
is manufactured fabricating solar cells directly onto the surface
of the wing but due to the current costs incurred for this process
are high using an external solar cell mounted on the mast
of the wind turbine is the feasible option. So this design aims
to utilizing two techniques of electricity generation using renewable
resources and fusing them together to develop a relatively
new method of energy generation.
3 HISTORY
The first known practical wind power plants were built
in Sistan, an Eastern province of Iran, from the 7th century.
Wind power first appeared in Europe during the Middle Ages.
The first historical records of their use in England date to the
11th or 12th centuries and there are reports of German
crusaders taking their windmill-making skills to Syria
around 1190. By the 14th century, Dutch windmills were in
use to drain areas of the Rhine delta.
The environmental impact of wind power when compared to
the environmental impacts of fossil fuels is relatively minor.
There are no direct greenhouse gas emissions from the generation
of electricity using wind turbines, and every 1 MWh of
electricity generated by a wind turbine results in a drop of 0.8-
0.9 t in greenhouse gas emissions when compared to a power
plant using conventional fuels. 1These benefits have propelled
the efforts of improving wind turbine technologies thus
improving their efficiency and net power output.
Worldwide there are now over two hundred thousand wind
turbines operating, with a total nameplate capacity of
432 GW as of end 2015. As of 2011, 83 countries around the
world were using wind power on a commercial basis. The size
of wind turbines has multiplied over the past 25 years and 5
MW wind turbine rotor has a diameter of up to 130 meters.
Likewise, the tower height of the power plants has increased
from 22 meters to over 140 meters.
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Omkar Bhogale, Mayank Dedhia and Tanmay Dhuri are currently pursuing
Bachelors’ degree in Mechanical Engineering at Thakur College of Engineering
and Technology, Mumbai, India.
International Journal of Scientific & Engineering Research, Volume 8, Issue 1, January-2017
ISSN 2229-5518
IJSER © 2017
http://www.ijser.org
4 WORKING
Humanity has been studying and borrowing designs and solutions
from the surrounding nature for many years. In the same
way we are trying to design and replicate the flying motion of
hummingbirds which allows them to fly and hover at the
same position.
Instead of three spinning blades that take up a lot of space and
need to be installed high off the ground, the turbine uses a
pair of wings that move back and forth in a figure-eight motion
in the breeze.3
The wind will force the wings to move in figure 8 which is a to
and fro motion. It is further converted to rotational motion
due to the mechanism (Fig C) and design of the turbine.
Lift Force: The lift force is one of the major force components
exerted on an airfoil blade section inserted in a moving fluid &
acts normal to the fluid flow direction. This force is a consequence
of the uneven pressure distribution over the blade surfaces.
Fig(a) Fig(b)
Force analysis of wing blade
Fig (c)-Proposed mechanism in order to convert the flapping
motion to rotary motion.
Fig(d)-Proposed blade design for wing-T.V
During down stroke phase (A to B) and upstroke phase (C to
D), the wing moves following 8 figure trajectory and converts
the totality of the resultant R (Drag+Lift). The resultant R remains
always tangential to the wing’s trajectory.(Fig.a and
Fig.b)
During the 2 short phases (D to A) and (B to C), the aerodynamic
resistance is quasi nil since the angle of attack becomes
equal to zero.
Different types and design configurations (Fig d) for wind
turbine: A great degree of design versatility is available in the
wind turbines design configurations. There are a few problems
inherent to the currently available designs including low
starting torque, turbine blade lift forces, lower efficiency, poor
building and foundation integration, etc.
The drag force acts in the direction of the fluid flowing. Drag
occurs due to the viscous friction forces on the airfoil surfaces,
and the unequal pressure on surfaces of the airfoil. Drag is a
function of the relative wind velocity at the rotor surface,
which is the difference between the wind speed and the speed
of the surface.
5 FLAPPING WING MECHANISM
Ideally the proposed mechanism would provide the most
compact solution to attain the flapping motion but due to the
increased surface contact the losses occurring due to friction
would be much greater. So the mechanism to achieve the infinite
path is designed based on a concept called, Duke Engine.
It is an axial engine mechanism where the reciprocating motion
of pistons is converted to rotary motion using an inclined
crank. This mechanism is ideal as first and second order vibrations
are negligible which make the system much more stable.
5The proposed mechanism helps to achieve the flapping motion
in the required infinite path and thus ensures stability of
the entire structure.
International Journal of Scientific & Engineering Research, Volume 8, Issue 1, January-2017
ISSN 2229-5518
IJSER © 2017
http://www.ijser.org
Fig (c)-Actual mechanism in order to convert the flapping motion to
rotary motion
The mechanism we have developed consists of a circular arrangement
of pistons held in a cylindrical block. Each piston
has two connecting rods at both ends attached by ball joints.
At the top the flapping wing is attached to the piston rods. At
the bottom each connecting rod is attached to a disc which is
further attached with an inclined connection rod. This rod
helps in rotating the drive shaft. Thus the sequence of motion
is as follows: Flapping to Reciprocating to Rotary. The use of a
universal joint at the center of the supporting disc helps to
ensure that at whatever angle the dice is rotation the power is
always efficiently transmitted to the drive shaft. Using the ball
joints at each ends of the connecting rods helps in smoothly
achieving the flapping motion without straining any components
of the mechanism. This prototype is inspired by the
Duke Engine mechanism and it is adapted and modified to
suit the requirements of the wind turbine.
6 INDUSTRIAL APPLICATION
Project has utility in the energy sector. The design allows the
turbine to be compact. Combination of two sources helps to
improve the power output. With this unique Bio design, vertical
axis converters could be widely adopted across various
areas including onshore and offshore They could be installed
for individual use (eg.to power a house) or grouped in a large
wind farm. We are aiming to achieve at least 5kW power generation
from each turbine purely on wind power. Additionally
deploying the solar panels would help jump the power output
by another 2kW thus making the expected output reach 7kW.
Since this project involves the synergistic combination of two
very different technologies to generate electricity it’s a completely
new approach towards energy generation from renewable
sources of energy. Also the design of this wind turbine is
very compact allowing it to be installed in very tight spaces.
Considering this the density of turbines in per sq. meter area
can be increased thus giving higher electricity generation rate.
7 CONCLUSION
The project is a novel approach towards energy generation
and we are trying to implement a new design in more efficient
and compact form. The flapping design helps to mimic the bio
mechanics of birds hence birds are also alerted and the fatalities
to birds can be significantly reduced. The higher density of
turbines per sq.metre means that the net power output can be
increased than a conventional wind turbine. The flapping motion
inspired by humming birds and the mechanism utilized
ensure that the vibrations transmitted are least and thus the
turbine can be safely installed atop buildings and skyscrapers
in urban areas. The combination of solar cells with wind power
means that higher power output in relatively less space
.Thus the flapping wing wind turbine is the viable alternative
to conventional wind energy technologies.
8 REFERENCES
1 2013: VTT Technical Research Centre of Finland. (in Finnish) – summary at
end of document
2 Bolin K et al. Infrasound and low frequency noise from wind turbines: exposure
and health effects. Environmental Res Let 2011
3 Altamont Pass Wind Resources Area (APWRA) Conservation Plan.
http://www.apwraconservationplan.org/index.html. accessed June 2011
4 Wind turbine paper – AIMU PAPERS
5 ISSN(Online):2347-3878,ImpactFactor(2015):
3.791(http://www.ijser.in/archives/v4i10/IJSER15974.pdf)
6 William McKinneyandJames DeLaurier. “Wingmill: An Oscillating-Wing
Windmill”,Journal of Energy, Vol. 5, No. 2 (1981), pp. 109-115
7 Duke Engines-New Zealand