15-12-2012, 01:57 PM
Design and Manufacture of a Micro Zero Head Turbine for Power Generation
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Abstract
A zero head water turbine has been used as a source of
power generation where construction of a dam for the head is not
required. It works on natural flow of water to generate a specific
power output. The power is however limited by flow of water
which is sufficient to keep generate a suitable number of
revolutions per minutes for the blades. Present research was
aimed to design and manufacture a micro zero head turbine
which could produce sufficient power to light a couple of energy
saver bulbs upto a wattage of 50 to 60 that can suffice the lighting
requirements of far flung villagers and dwellers having access to
natural streams of water but no electricity supply. It resulted in
design and fabrication of one such turbine which was able to
generate a power of approximately 50 watts at a free stream
velocity of 1.2 meter/second. Findings of this research were quite
in harmony with theoretical results which may be used for
increasing the size of micro turbine along with a proportionate
rise in generated power.
INTRODUCTION
Micro-hydel power (MHP) technology has matured
over a period of time. Centuries back, man learnt how to
make use of water for power generation and even
presently, in some countries primitive hydraulic devices
could be found. Now a day’s MHP are being developed
using modern design tools and technologies. These are
being used for power generation at far flung places [2]
where naturally flowing streams of water exist in
abundance [3]. Such power generation initiatives are
being duly supported by the local governments.
Additional advantages of a Micro zero head turbine are
high efficiency in low speed currents, little resistance to the
onward force of a tide and it also allows marine life to
harmlessly escape from the rotor blade. Investigations
regarding the influence of design parameters in low head axial
flow turbines like blade profiles, blade height and blade
number for micro-hydro application continue to be inadequate,
even though there is a need and potential for the application of
such turbines [1]. Investigations have been made to analyze
the cost of various components of low head run-of-river small
hydropower projects based on the actual quantity and the
prevailing market price of each item [5].
DESIGN OF PROTOTYPE
Primary consideration for Micro Zero head turbine design
was that it should fit a limited space ranging from 1 to 4 feet
width of the free stream of water flow in far flung areas and
must have minimum of the following geometric
specifications:-
a. Perpendicular distance from shaft centre to force
exerting on blade = 130mm
b. Pulley radius = 110mm
c. Blade dimension = 100 x 100 mm²
d. Blade shape = semi circular
e. Number of blades = 08
f. Flow velocity = 0.5 m/s, 1m/s, 1.2m/s, 1.5m/s
These dimensions were a result of required power
generation and subsequently it was to be tested
experimentally. Other design parameters included variable
flow rates to provide different power values, out flow of one
blade not to obstruct the other and availability of continuous
TURBINE TESTING
The turbine was tested in a free water stream
environment. Force applied on the buckets, torque generated,
power output and electrical load which could be powered by
the turbine was evaluated for various flow velocities. The
relationships observed are shown in Fig. 7.
It may be observed that the power values increased
exponentialy at a higher gradient. This trend was followed by
powered electrical load and Force generated by the water
stream at higher velocities. The exact values of these
parameters are given at the end of this paper in table 1.0. The
testing is however shown in Fig. 9.
CONCLUSION
Present research may be concluded by stating that such
turbines could be used at regions where there is abundance of
free water streams; small and large. The sizes of the turbines
could be various as per the power requirements of users. This
type of turbine could be an economical source of power
generation where electric power could not be provided due to
absence of power transmission lines and requirements of huge
investments on infrastructure. Such initiatives if supported by
local governments could provide the fruits of electric power to
dwellers of distant lands.