domestic hydro power plant
TRANSCRIPT
A Seminar Report on
“DOMESTIC HYDROPOWER PLANT”
Submitted toVISVESVARAYA TECHNOLOGICAL UNIVERSITY
BELGAUM
BACHELOR OF ENGINEERING
INMECHANICAL ENGINEERING
Under the Guidance ofMr. VENKATE GOWDA.T
B.E., M.Tech (Design)
Lecturer, Department of Mechanical Engineering
AMARDEEP 1SG08ME004
SAPTHAGIRI COLLEGE OF ENGINEERINGBangalore-560 057
SAPTHAGIRI COLLEGE OF ENGINEERING# 14/5, Chikkasandra, Hesaraghatta Main Road, Bangalore-560
057
Department of Mechanical Engineering
CERTIFICATE
Certified that the seminar report entitled “DOMESTIC
HYDROPOWER PLANT” carried out by Mr. AMARDEEP,
USN – 1SG08ME004, a bonafide student of SAPTHAGIRI
COLLEGE OF ENGINEERING in partial fulfillment for the
award of Bachelor of Engineering in Mechanical Engineering of
the Visvesvaraya Technological University, Belgaum during the
year 2011-12.
Name & Signature of the Guide Name & Signature of the H.O.D
Name & Signature of the Seminar Co-ordinator
ACKNOWLEDGEMENT
I express my deep gratitude to almighty, the supreme guide, for bestowing
his blessings upon me in my entire endeavor.
I would to like to express my sincere thanks to Dr. S H. Manjunath , Head of
Department, Mechanical Engineering Department, Sapthagiri College of
Engineering for all his assistance.
I wish to express my deep sense of gratitude to Mr. Venkate Gowda.T,
lecturer, Department of Mechanical Engineering who guided me through-out
the seminar. His overall direction and guidance has been responsible for the
successful completion of the seminar.
I would also like to thank Lecturer Mr. for his valuable suggestions.
Finally, I would like to thank all the faculty members of the Department of
Mechanical Engineering and my friends for their constant support and
encouragement.
ABSTRACT
Hydropower plants (HPP) are energy capacities which have negligible operation costs comparing with the high investments because of the water as natural and sustainable energy resource. The energy generation from hydropower plants cover a small part of total electricity needs in mainly because of limited water inflow. On the other side comparing with the fossil fired power plants, the hydropower plants are environmentally friendly and sustainable resource of energy. The electricity generation is strongly dependant on lignite thermal power plants (TPP)which can cover 70-80 % , and the rest is covered from hydropower and electricity import. The hydropower potential in existing HPP is between 800 GWh and 1500 GWh of electricity generation in a year depends on hydrology.The main HPP in Macedonia are Vrutok, Vrben and Raven in Mavrovo basin, Globocica and Spilje inCrn Drim basin, Tikves from Crna reka basin, and Kozjak, Sv. Petka and Matka from Treska basin.This paper gives the overall of technical characteristics of existing HPP units in Macedonia, as well aseconomical and technical parameters for new candidates. On the basis of natural water inflow bymonth, it will be calculated the monthly electricity generation, water discharge, variation of water levelin the reservoirs, and others. On the other side the paper will give some statistical points of naturalwater inflow and energy generation of the HPP taking into account the hydrology conditions for wet,average or dry season.
1. INTRODUCTION:
Hydropower is energy from water sources such as the ocean, rivers and waterfalls. “microhydro” means which can apply to sites ranging from a tiny scheme to electrify a single home,to a few hundred kilowatts for selling into the National Grid. Small-scale hydropower is one of the most cost-effective and reliable energy technologies to be considered for providingclean electricity generation. The key advantages of small hydro are:_ High efficiency (70 - 90%), by far the best of all energy technologies._ High capacity factor (typically >50%)_ High level of predictability, varying with annual rainfall patterns_ Slow rate of change; the output power varies only gradually from day to day (not from minute to minute)._ A good correlation with demand i.e. output is maximum in winter._ It is a long-lasting and robust technology; systems can readily be engineered to last for 50 years or more.It is also environmentally benign. Small hydro is in most cases “run-of-river”; in other wordsany dam or barrage is quite small, usually just a weir, and little or no water is stored.Therefore run-of-river installations do not have the same kinds of adverse effect on the local environment as large-scale hydro.
2. BLOCK DIAGRAM:
Fig 2:
In the absence of an applied field, MR fluids are reasonably
well approximated as Newtonian liquids. For most engineering
applications a simple Bingham plastic model is effective at
describing the essential, field-dependent fluid characteristics. A
Bingham plastic is a non-Newtonian fluid whose yield stress must
be exceeded before flow can begin; thereafter, the rate-of-shear vs.
shear stress curve is linear. In this model, the total yield stress is
given by:
Where:
= yield stress caused by applied magnetic field
= magnitude of magnetic field
= shear rate
= field-independent plastic viscosity defined as the slope of
the measured shear stress vs. shear strain rate relationship,
i.e., at H=0.
Fig 2.1: Graph to illustrate Viscosity v/s Shear Rate in a MR Fluid.
3. WORKING PRINCIPLE:
Applying a magnetic field to Magnetorheological fluids
causes particles in the fluid to align into chains.
Fig 3.
When some low-density MR fluids are exposed to rapidly
alternating magnetic fields, their internal particles clump together.
Over time they settle into a pattern of shapes that look a bit like
fish viewed from the top of a tank. Such clumpy MR fluids don’t
stiffen as they should when magnetized. The fish tank pattern is
fragile and takes about an hour to fully develop. It doesn’t occur in
MR fluids that are constantly mixed and agitated, as in a car’s
suspension, but it could prove troublesome in other situations.
Fig 3.1.
Above: The structure of particles in an MR fluid gradually changes
when an alternating magnetic field is applied. The leftmost picture
shows an MR fluid after 1 second of exposure to a fast-changing
magnetic field. The suspended particles form a strong, fibrous
network. The pictures to the right show the fluid after 3 minutes,
15 minutes and 1 hour of exposure. The particles have formed
clumps that offer little structural support.
4. WHAT MAKES A GOOD M R FLUID?
The most common response to the question of what makes a
good MR fluid is likely to be "high yield strength" or "non-
settling". However, those particular features are perhaps not the
most critical when it comes to ultimate success of a
Magnetorheological fluid. The most challenging barriers to the
successful commercialization of MR fluids and devices have
actually been less academic concerns.
As anyone who has made MR fluids knows, it is not hard to
make a strong MR fluid. Over fifty years ago both Rabinow and
Winslow described basic MR fluid formulations that were every bit
as strong as fluids today. A typical MR fluid used by Rabinow
consisted of 9 parts by weight of carbonyl iron to one part of
silicone oil, petroleum oil or kerosene.1 To this suspension he
would optionally add grease or other thixotropic additive to
improve settling stability. The strength of Rabinow’s MR fluid can
be estimated from the result of a simple demonstration that he
performed. Rabinow was able to suspend the weight of a young
woman from a simple direct shear MR fluid device. He described
the device as having a total shear area of 8 square inches and the
weight of the woman as 117 pounds. For this demonstration to be
successful it was thus necessary for the MR fluid to have yield
strength of at least 100 KPa.
MR fluids made by Winslow were likely to have been
equally as strong. A typical fluid described by Winslow consisted
of 10 parts by weight of carbonyl iron suspended in mineral oil.2
To this suspension Winslow would add ferrous naphthenate or
ferrous oleateas a dispersant and a metal soap such as lithium
stearate or sodium stearate as thixotropic additive. The
formulations described by Rabinow and Winslow are relatively
easy to make. The yield strength of the resulting MR fluids is
entirely adequate for most applications. Additionally, the stability
of these suspensions is remarkably good. It is certainly adequate
for most common types of MR fluid application. As early as 1950
Rabinow pointed out that complete suspension stability, i.e. no
supernatant clear layer formation, was not necessary for most MR
fluid devices. MR fluid dampers and rotary brakes are in general
highly efficient mixing devices.
5. M R FLUIDS IN DAMPERS:
As motion control systems become more refined, vibration
characteristics become more important to a system’s overall design
and functionality. Engineers, however, have tended to look at
motion control and vibration as separate issues. Motion control, it
might be said, presents fairly familiar design engineering problems
while vibration suggests more subtle problems. Few design
engineers have either the hands-on experience or the training to
address both sets of problems in a single design solution.
Fig 5: MR Fluid Damper
Most devices use MR fluids in a valve mode, direct-shear
mode, or combination of these two modes. Examples of valve
mode devices include servo valves, dampers, and shock absorbers.
Examples of direct-shear mode devices include clutches, brakes,
and variable friction dampers
. In valve mode When the piston in a MR fluid damper
moves, the MR fluid jets through the orifices quite rapidly causing
it to swirl and eddy vigorously even for low piston speed.
Similarly, the shear motion that occurs in a MR brake causes
vigorous fluid motion. As long as the MR fluid does not settle into
a hard sediment, normal motion of the device is generally
sufficient to cause sufficient flow to quickly remix any stratified
MR fluid back to a homogeneous state. For a small MR fluid
damper two or three strokes of a damper that has sat motionless for
several months are sufficient to return it to a completely remixed
condition.
Except for very special cases such as seismic dampers, lack
of complete suspension stability is not a necessity. It is sufficient
for most applications to have a MR fluid that soft settles – upon
standing a clear layer may form at the top of the fluid but the
sediment remains soft and easily remixed. Attempting to make
these MR fluids absolutely stable may actually compromise their
performance in a device. One of the areas where MR fluids find
their greatest application is in linear dampers that effect semi-
active control. These include small MR fluid dampers for
controlling the motion of suspended seats in heavy duty trucks,
larger MR fluid dampers for use as primary suspension shock
absorbers and struts in passenger automobiles and special purpose
MR fluid dampers for use in prosthetic devices.
In all of these devices one of the most important fluid
properties is a low-off state viscosity. While in all of these
examples having a MR fluid with high yield strength in the on-
state is important, it is equally important that the fluid also have a
very low off state. The very ability of an MR fluid device to be
effective at enabling a semi-active control strategy such as “sky -
hook” damping depends on being able to achieve a sufficiently low
off-state. Care must be taken in choosing fluid stabilizing additives
so that they do not adversely affect the off-state viscosity.
Earthquake dampers and other some other special
applications in which the device will sit quiescent for very long
periods of time represent special cases where fluid stability issues
may have overriding importance. Because of the transient nature of
seismic events these dampers never see regular motion, which can
be relied on to keep the fluid mixed. This lack of motion also has it
benefit. Unlike dampers used in highly dynamic environments,
seismic dampers do not need to sustain millions of cycles. The fact
that durability and wear are not issues gives the fluid designer
grater latitude to formulate a highly stable fluid. MR fluids for
these applications are typically formulated as shearing thinning
thixotropic gels.
6. APPLICATIONS OF M R FLUIDS:
MR fluids find a variety of applications in almost all the
vibration control systems. It is now widely used in automobile
suspensions, seat suspensions, clutches, robotics, design of
buildings and bridges, home appliances like washing machines etc.
Before discussing the above said applications in detail it is
desirable to go through the behavior of MR fluids on different
types of loading and what are the design considerations provided to
compensate this.
6.1 MR fluids on impact and shock loading:
Investigations on the design of controllable
Magnetorheological (MR) fluid devices have focused heavily on
low velocity and frequency applications. The extensive work in
this area has led to a good understanding of MR fluid properties at
low velocities and frequencies. However, the issues concerning
MR fluid behavior in impact and shock applications are relatively
unknown.
To investigate MR fluid properties in this regime, MR
dampers were subjected to impulsive loads. A drop-tower test
facility was developed to simulate the impact events. The design
includes a guided drop-mass released from variable heights to
achieve different impact energies. The nominal drop-mass is 55 lbs
and additional weight may be added to reach a maximum of 500
lbs. Throughout this study; however, the nominal drop-mass of 55
lbs was used. Five drop-heights were investigated, 12, 24, 48, 72
and 96 inches, corresponding to actual impact velocities of 86, 127,
182, 224 and 260 in/s.
Two fundamental MR damper configurations were tested, a
double-ended piston design and a mono-tube with nitrogen
accumulator. To separate the dynamics of the MR fluid from the
dynamics of the current source, each damper received a constant
supply current before the impact event. A total of five supply
currents were investigated for each impact velocity.
After reviewing the results, it was concluded that the effect of
energizing the MR fluid only leads to “controllability” below a
certain fluid velocity for the double-ended design. In other words,
until the fluid velocity dropped below some threshold, the MR
fluid behaved as if it was not energized, regardless of the strength
of the magnetic field. Controllability was defined when greater
supply currents yielded larger damping forces.
For the mono-tube design, it was not possible to estimate the
fluid velocity due to the dynamics of the accumulator. It was
shown that the MR fluid was unable to travel through the gap fast
enough during the initial impact, resulting in the damper piston and
accumulator piston traveling in unison. Once the accumulator
bottomed out, the fluid was forced through the gap. However, due
to the energy stored in the accumulator and the probable fluid
vaporization, it was impossible to determine the fluid velocity and
in many cases the damper did not appear to become controllable.
In conclusion, the two designs were compared and general
recommendations on designing MR dampers for impulsive loading
were made. Possible directions for future research were presented
as well.
6.2 MR fluid in automobile clutches
MR fluids are increasingly being considered in variety of
devices such as shock absorbers, vibration insulators, brakes or
clutches. The activation of MRF clutch’s built-in magnetic field
causes a fast and dramatic change in the apparent viscosity of the MR
fluid contained in the clutch. The fluid changes state from liquid to
semi-solid in about 6 milliseconds. The result is a clutch with an
infinitely variable torque output.
6.3 Double plate MRF clutch design:
Bans Bach, proposed a double-plate and a multi-plate MRF
torque transfer apparatus with a controller that adjusts the input
current. The apparatus is proposed to be placed between the engine of
a car and its differential. Gopalswamy suggested a MRF clutch to
minimize reluctance for fan clutches. Gopalswamy also studied a
controllable multi-plate MR transmission clutch. This clutch was also
designed to be placed between the engine and differential. Hampton
described a design of MRF coupling with reduced air gaps and high
magnetic flux density. Carlson proposed a MR brake with an
integrated flywheel.
The figure below shows the prototype of a double plate magneto
rheological fluid clutch.
Fig 6.3: Double plate MRF clutch design
The MR fluid is located in the gap between the input and output
plates, with the diameter of 51.94 mm. These plates are connected to
30 mm diameter input and output shafts. The shafts are supported by
deep groove ball bearings, which are press-fitted into the side caps.
The electromagnet circuit of this clutch consists of an electromagnetic
coil, which is wound around an electromagnetic core. This assembly
is located inside a 152.4 mm outer diameter casing with 6.35 mm wall
thickness, which is also acting as a return path for the magnetic field.
Two O-rings are located in the grooves machined on the
circumferences of plates to prevent leakage of MR fluid. The MRF
clutch is activated by a power supply connected to two ends of the
Electromagnet. The total width of the clutch is 31.75 mm.
The graph above shows magnetic field strength as a function of
radius in the MRF section. From the graph it can be observed that the
magnetic field increases with increasing radial distance from the
rotational axis. This is a desirable outcome since the contribution of
the resulting shear yield stress on the torque transmitted increases
with increasing radial distance.
The performance of a double-plate magneto-rheological fluid
limited slip differential clutch is studied using two types of MR
fluids. Theoretical and experimental analyses have illustrated that this
MR fluid clutch can transfer high controllable torques with a very fast
time response.
6.4 MR fluid in automotive suspensions:
Fig 6.4: Automotive Suspension.
MR technology enables new levels of performance in
automotive primary suspension systems. Shock absorbers incorporate
magneto rheological fluids to provide real-time optimization of
suspension damping characteristics that improve ride and handling.
MR fluid controllable damping technology outperforms all existing
passive and active suspension systems.
The MR fluid sponge damper requires neither seals nor
bearings, and uses the same inexpensive components found in
existing passive dampers, but with a few important modifications.
The damper consists of a layer of open-celled, polyurethane foam, or
other suitable absorbent matrix materials, saturated with ~3 ml of MR
fluid surrounding a steel bobbin and coil
Together these elements form a piston on the end of the shaft
that is free to move axially inside a steel housing that provides the
magnetic flux return path. Damping force is proportional to the
sponge’s active area.
The application of a magnetic field causes the MR fluid in the
matrix to develop yield strength and resist shear motion. The amount
of force produced is proportional to the area of active MR sponge that
is exposed to the magnetic field. This arrangement can be applied in
both linear and rotary configurations wherever a direct shear mode of
operation would be used.
6.5 MR fluid in washing machines:
A good example of unwanted vibratory motion is a washing
machine in its spin cycle trying to walk out of the room. MR damping
can correct this and other problem vibrations.
The common household washing machine represents a standard
compromise between controlling vibration associated with the spin
cycle and achieving optimum system performance and efficiency. The
tub in a conventional machine is suspended by a number of coil
springs that provide mechanical support as well as vibration isolation
at high frequency. To prevent potentially damaging vibratory
excursions when the drum velocity passes through resonance as it
accelerates during the ramp-up to the spin cycle, static vibration
dampers are added to the suspension.
Conventional dampers easily control the tub’s motion at
resonance; they can significantly degrade high-speed vibration
isolation. This tendency limits the size of the tub and to some extent
dictates the dimensions of the housing that must accommodate the
overall motion of the tub.
Because many households have only a washing machine and not
a dryer, tub speeds are reaching 2000 rpm, effectively becoming
centrifuges that remove almost all the water from the wash load. In
fact, manufacturers have had to reduce the size of the drain holes in
the tub to prevent extrusion of small items of clothing during the spin
cycle.
To achieve this level of performance, manufacturers have
incorporated a controllable damping system designed around
Magnetorheological (MR) fluid.
Fig 6.5: MR Fluid in washing machine.
Conventional springs and Magnetorheological dampers work
together to stabilize a home washing machine during the spin cycle.
The dampers control vibrations as the tub passes through resonance;
at the highest speeds the dampers are switched off and vibration
isolation is provided by the mechanical springs that support the tub.
These can simply be turned off at high spin speeds for an increased
degree of vibration isolation.
Fig 6.5.2: MR Fluid dampers in washing machine.
By activating the damper while the washing machine tub is
passing through resonance, a degree of vibration control is achieved
not possible with conventional springs alone. The damping
mechanism is switched off at the greatest speeds, when the
mechanical springs provide vibration isolation.
At high speed, the MR sponge dampers are turned off to enable
a high level of vibration isolation. With enhanced vibration control,
the drum may be made larger or the housing smaller since it must
accommodate less overall tub motion. Ideally, each of a pair of
controllable dampers would have to provide 50–150 N of damping
force when energized and a low residual force of <5 N when turned
off.
The application of Magnetorheological fluids for damping is a
unique and novel approach to an age-old problem. The repetitive
"thud" of a washing machine imbalance is inefficient. It does not dry
the clothes as well as it should and the peak energy demand is higher.
Then there is the cost in energy, to dry wetter clothes. Vibration
should be viewed as wasted energy.
6.6 MR fluid in seismic and wind mitigation:
Civil engineers in the construction industry are incorporating
MR Technology into the structural engineering of buildings and
bridges. The system is relatively inexpensive, needs little
maintenance and requires very little power to operate. A damping
system utilizing MR fluid dampers works similarly to an automotive
shock absorber, protecting the structure from earthquakes and
windstorms. When properly harnessed, the adaptability of MR
dampers can help protect a building or bridge during a severe
earthquake.
Real-time damping is controlled by the increase in yield stress of the
MR fluid in response to magnetic field strength. The response time of
the fluid damping is on average 60-milliseconds as the magnetic field
is changed. Seismic motion causes one floor to shear relative to the
next floor as low-order modes of the building are excited. Excessive
motion that is potentially damaging to the building and its contents is
controlled by dissipating mechanical energy in a distributed array of
dampers.
In giant bridges stay cables are prone to vibration due to wind
and rain effects. Smart dampers have the potential efficiency several
times that of standard oil dampers. MR Dampers are currently being
used on the Dongting Bridge in China.
So Magnetorheological fluid dampers can be considered as an
excellent solution for all vibrational problems associated with
constructional industries
6.7 MR fluid in seat suspensions:
In today’s pupil transportation, trucking and transit industries,
driver safety can never be compromised. MR fluid technology has
proven capability to reduce topping and bottoming: Bottoming that
can injure drivers and Topping that can lead to loss of control of the
vehicle.
Seating equipped with MR dampers is the only product that
offers both safety and health benefits for drivers. Unlike standard air
suspended seats, which compromise shock and vibration control, the
MR technology is the only solution that automatically adapts to both
the driver’s body weight and continually changing levels of shock and
road vibration, improving driver responsiveness and control while
reducing fatigue and risk of injury.
6.8 MR fluid as robot blood:
Astronauts onboard the International Space Station are studying
strange fluids that might one day flow in the veins of robots. MR
fluids are liquids that harden or change shape when they feel a
magnetic field.
The nervous systems of future robots might use MR fluids to move
joints and limbs in lifelike fashion
7. ADVANTAGES OF M R DAMPERS:
The MR fluid sponge damper requires neither seals nor
bearings, and uses the same inexpensive components found in
existing passive dampers, but with a few important modifications.
The damper consists of a layer of open-celled, polyurethane foam, or
other suitable absorbent matrix materials, saturated with ~3 ml of MR
fluid surrounding a steel bobbin and coil.
During passage through resonance, these controllable dampers
may be energized to provide a high level of damping which protects
the associated machine.
At high speed, the MR sponge dampers are turned off to enable
a high level of vibration isolation. Ideally, each of a pair of
controllable dampers would have to provide 50–150 N of damping
force when energized and a low residual force of <5 N when turned
off.
The power requirements for controllable MR fluid dampers are
so low that a net energy saving might be realized. Effective resonance
control typically requires ~10 W of input power to the MR dampers
for ~5–10 s, as the drum speed ramps through criticality. The amount
of power is readily available from existing onboard electronics in a
standard machine.
This can be explained with the help of the graph transmitted
force vs spin speed given below.
The rotational motion of the inner drum or agitator in a washing
machine, along with any load imbalance, creates a disturbing force
that excites vibratory motion of the tub that can become excessive
when the drum speed is near or at resonance.
Many of the benefits of passive damping schemes built around MR
technology are intuitive:
i. Efficiency
Washing machines achieve greater performance in terms
of higher spin speeds without the increased energy
consumption of more powerful motors.
With heightened vibration control, tubs in washing
machines can be designed larger and the housing smaller.
Machines can accurately weigh loads and thus control the
use of water and detergent.
Damages caused to the machine during resonance can be
avoided.
ii. Functionality
The damping system uses onboard electronics.
No additional operator control is required.
MR provides real-time controllability.
iii. Cost
Because existing materials are used, the slight increase in
materials cost is balanced by improved energy efficiency.
iv. System Integration
Additional electronic controls are easily adaptable to the
existing machine’s electronics footprint.
8. LIMITATIONS OF M R DAMPERS:
One major limitation of these MR dampers is the high cost
required for the installation. This can be neglected taking into account
the considerable increase in the efficiency of the associated machine.
MR dampers are now using temporary magnets which require
an applied magnetic field of 150–250 kA/m. Latest technologies
permits the use of permanent magnets also.
9. ADVANCEMENT IN M R FLUID TECHNOLOGY:
In addition to cost-sensitive applications such as washing
machines, MR fluid dampers are being used in rotary brakes for
exercise equipment and pneumatic systems; in complete semi active
damper systems for heavy-duty truck seat suspensions; in adjustable
linear shock absorbers for racing cars; and in semi active suspensions
for passenger cars.
Now under commercial development are very large MF fluid
dampers designed for seismic damage mitigation in civil engineering
structures such as buildings and bridges.
Finally, the technology is being investigated for applications in
vehicular steer-by-wire devices and medical equipment such as the
joints of prosthetic limbs.
The nervous systems of future robots might use MR fluids to
move joints and limbs in lifelike fashion. There are many potential
applications that make these fluids very exciting." For example, MR
fluids flowing in the veins of robots might one day animate hands and
limbs that move as naturally as any humans. Book makers could
publish rippling magnetic texts in Braille that blind readers could
actually scroll and edit. It might even be possible to train student
surgeons using synthetic patients with MR organs that flex and slices
like the real thing.
New developments in MR fluid technology allow the use of
permanent magnets which has lots of advantages. The question often
arises asking if it is possible to use a permanent magnet to bias a MR
fluid valve or device at a mid-range condition. Current could then be
applied to the accompanying electromagnetic coil to cancel the
magnetic field and open the valve. Alternatively, a reverse current
could be applied to the coil to add to the magnetic field taking the
device to a higher–range condition. One motivation for creating such
a system is to provide a fail-safe mode of operation wherein the
device remains in a locked condition when power is lost. Another
motivation may be energy conservation in systems intended to remain
closed or locked for extended periods of time and then only open
momentarily.
10. MORE FAR-OUT APPLICATIONS OF M R FLUIDS:
Magneto-liquid mirror telescopes that bend and deform to
cancel the twinkling of starlight.
Prosthetic limbs for humans (a prosthetic knee based on
Lord Corporation MR fluid technology is already
available.)
Active engine mounts that reduce vibration and quiet noise
before it can get into a vehicle.
Shock absorbers for payloads in the space shuttle.
Active hand grips that conform to the shape of each
individual hand or fingers.
11. CONCLUSION:
Magneto rheological fluids are actually amazing magnetic
fluids. MR fluid development is of course a balancing act that is
highly coupled with MR device design. MR fluid durability and life
have been found to be more significant barriers to commercial
success than yield strength or stability. Amenability of a particular
MR fluid formulation to being scaled to volume production must also
be considered. Challenges for future MR fluid development are fluids
that operate in the high shear regime of 104 to 106 sec-1.thus MR
fluids can be considered as a better way of controlling vibrations. The
key to success in all of these implementations is the ability of MR
Fig 10
fluid to rapidly change its rheological properties upon exposure to an
applied magnetic field.
Fig 11. Magnetorheological Fluid Suspensions
12. REFERENCES:
1. J. David Carlson, “What Makes a Good MR Fluid?,” 8th
International Conference on ER Fluids and MR Fluids Suspensions,
Nice, July 9-13, 2001.
2. LORD Materials Division, “Permanent - Electromagnet System,”
Engineering Note, March 2002.
3. Mark R. Jolly, Jonathan W. Bender, and J. David Carlson,
“Properties and Applications of Commercial Magnetorheological
Fluids,” SPIE 5th Annual Int Symposium on Smart Structures and
Materials, San Diego, CA, March 15, 1998.
4. T. Simon, F. Reitich, M. R. Jolly, K. Ito, and H. T. Banks (2001)
“On the Effective Magnetic Properties of Magnetorheological
Fluids,” Mathematical and Computer Modeling, 33, 273-284.
5. M.R. Jolly (1999) “Properties and Applications of
Magnetorheological Fluids,” (Invited) Proc. of MRS Fall Meeting,
Vol. 604, Boston, MA, Nov. 29-Dec. 3, 1999.
6. J. D. Carlson, “Low-Cost MR Fluid Sponge Devices,” J. Intelligent
Systems and Structures, 10 (1999) 589-594.
7. J. David Carlson, “New Cost Effective Braking, Damping, and
Vibration Control Devices Made with Magnetorheological Fluid,”
Materials Technology, 13/3 (1998) 96-99.
8. A. J. Margida, K. D. Weiss and J. D. Carlson, “Magnetorheological
Materials Based on Iron Alloy Particles,” Int. J. Mod. Physics B, 10
(1996) 3335-3341.
ABSTRACT:
Hydro power plants convert potential energy of water into electricity.
It is a clean source of energy .The water after generating electrical
power is available for irrigation and other purposes. The first use of
moving water to produce electricity was a waterwheel on the Fox
River in Wisconsin in 1882. Hydropower continued to play a major
role in the expansion of electrical service early in this century around
the world. Hydroelectric power plants generate from few kW to
thousands of MW. They are classified as micro hydro power plants
for the generating capacity less than 100 KW. Hydroelectric power
plants are much more reliable and efficient as a renewable and clean
source than the fossil fuel power plants. This resulted in upgrading of
small to medium sized hydroelectric generating stations wherever
there was an adequate supply of moving water and a need for
electricity. As electricity demand soared in the middle of this century
and the efficiency of coal and oil fueled power plants increased, small
hydro plants fell out of favor. Mega projects of hydro power plants
were developed. The majority of these power plants involved large
dams, which flooded big areas of land to provide water storage and
therefore a constant supply of electricity. In recent years, the
environmental impacts of such large hydro projects are being
identified as a cause for concern. It is becoming increasingly difficult
for developers to build new dams because of opposition from
environmentalists and people living on the land to be flooded.
Therefore the need has arisen to go for the small scale hydro electric
power plants in the range of mini and micro hydro power plants.
There are no micro hydro power plants in Malaysia and the smallest
category of hydro power plants in Malaysia is mini hydro with a
capacity between 500 kW to 100 kW. This paper discusses the
conceptual design and development of a micro hydro power
plant .The overall estimation and calculation of a 50 kW power plant
has been carried out. Software is also developed using MATLAB to
calculate the total head, discharge rate, type of turbine for the micro
hydro power plants, once the capacity is known.