Differentiation Analysis of Single and Dual Rotor Wind Turbine Torque Transmission System

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Int. J. Mech. Eng. & Rob. Res. 2014 Tipu Sultan et al., 2014
DIFFERENTIATION ANALYSIS OF SINGLE AND
DUAL ROTOR WIND TURBINE TORQUE
TRANSMISSION SYSTEM
Tipu Sultan1*, Anurag Gour1 and Mukeshpandey1
*Corresponding Author: Tipu Sultan,  [e-mail]
For the next leap in the sustainable technologies, we are under obligations not only to cope with
the warming global environment but also to conserve natural ecosystem and to coexist with
nature this study aims to analyse the comparison analysis of single and dual rotor wind turbine
torque transmission. For this purpose, we had analysed the gearbox transmission system of
single and dual rotor wind turbine. In a single rotor wind turbine system the gear transmission
system has parallel or planetary gear box arrangement but the dual rotor wind turbine system
had combination of planetary and parallel shaft gearbox arrangement.
Keywords: Wind power, Gears, CATIA, Torque, Betz limit, Wind speed, Shafts, Bearings
INTRODUCTION
Wind is one of the clean energy sources, and
its conversion to usable energy is important to
reduce fossil fuel dependency. In order to
obtain energy from wind, a lot of wind turbines
are being constructed. However, regions
having high wind energy density are finite. It is
one of the fastest growing energy resources
and it is going to have remarkable share in
the energy market. Thus, the consequences
of the connection of wind turbine, specifically
in the form of a wind farm, to the electrical grid
must be investigated from steady state,
dynamic and transient point of view. Different
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Int. J. Mech. Eng. & Rob. Res. 2014
1 School of Energy and Environmental Managment, UTD, RGPV Bhopal, MP, India.
approaches have been introduced to improve
the static and dynamic responses of the wind
turbines. Therefore, many researches to
increase energy efficiency of wind turbines
have been accomplished.Generally, horizontal
axis wind turbines having a single rotor are
used for conventional wind turbine systems.
According to Betz theory (Manwell et al.,
2005), the maximum energy conversion
efficiency of conventional wind turbines having
a single rotor is about 59%. Bycontrast, the
maximum efficiency obtained by two rotors
having the same area is increased to 64%.
based on this results, in order to increase the
Research Paper

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Int. J. Mech. Eng. & Rob. Res. 2014 Tipu Sultan et al., 2014
energy efficiency of wind turbines, some
researches for Counter-Rotating Wind
Turbines (CRWT) that have two rotors rotating
opposite direction at the same axis have been
progressed. Appa technology initiatives
(Appa, 2002) have established a proto model
of 6 kW counter rotating wind turbine in
California. the rotor performance data have
been measured and numerical predictions
using Blade Element Momentum (BEM)
method have been accomplished. Jung et al.
(2005) has constructed a 30 kW counter
rotating wind turbine system and has obtained
power curve experimentally and numerically.
inaddition, the effects of distance and diameter
ratio between two rotors have been
considered by using BEM method. Shen et al.
(2007) has used CFD code, ellipse 3d, to
predict performance of a counter rotating wind
turbine having two Nordtank 500 kw rotors. All
these researches mentioned above have
compared the performance of a counter
rotating wind turbine with that of single rotor
having half number of blades. However, these
comparisons are unfair because each rotor
configuration has different solidity (the ratio of
total blade areato rotor disk area). In this study,
for a fair comparison, aerodynamic
characteristics of a counter rotating wind
turbine were compared with that of a single
rotor having equal solidity as well as a single
rotor having half solidity. Through numerical
calculations of induction factors and power
coefficients for each rotor configuration, the
aerodynamic feasibility of a counter rotating
wind turbine was considered.
METHODOLOGY
Mechanical power transmission by multiplying
the angular speed under a constant
transmission ratio represents the function of a
large group of products known as
speedmultipliers. Most wind turbines and
hydro systems drive trains include a gearbox
to increase the speed of the turbine shaft to
the generator. An increase in speed is needed
because the turbines rotors turn at a much
lower speed than is required by most electrical
generators. The range in which the input
angular speed must be increased is 25-30
times the RPM.
Figure 1: Planetary Gearbox Arrangement
There are two basic types of gearboxes
used in wind turbines applications: parallel-
shaft gearboxes and planetary gearboxes. In
the first case, in order to obtain higher values
of the transmission ratio, multiple stages are
placed in series. This arrangement increases
the multiplication ratio but, in the same time,
increases the overall dimension. Unlike the
parallel-shaft gearboxes, the planetary
gearboxes have some significant differences:
the input and output shafts are coaxial, that
reduces the radial and axial dimensions;
there are sometimes multiple power
branches, so the loads on each gear are
reduced; the gearboxes are relatively light
and compact.