1. BHARAT HEAVY ELECTRICALS LIMITED, BHOPAL
REPORT ON WATER TURBINE MANUFACTURING
UNDER GUIDENCE
MR. D. PRABHAKAR (DGM WTM BLOCK-1)
SUBMITTED BY
KUSHAGRA PUNDEER
2. CERTIFICATE
This is to certify that KUSHAGRA PUNDEER a
student of INTERNATIONAL CENTRE OF
APPLIED SCIENCES, MANIPAL UNIVERSITY
has successfully completed his training with
from 2nd
to 14th
Jan 2012 under BHEL, Bhopal.
MR. D. PRABHAKAR
(DGM WTM BLOCK- 1)
3. ACKNOWLEDGEMENT
I am greatly thankful to B.H.E.L for providing me vital and
much needed practical experience in the field of machines
and manufacturing. I express my gratitude to Human
Resource and Development department for giving me a
chance to feel the industrial environment. I am also
thankful to the B.H.E.L engineers and the technical staff
for giving their precious time for helping me in
understanding various aspects of machine manufacturing
and their assembly. I am also thankful to my training co-
coordinator Mr. D Prabhakar (DGM WTM block-1) and his
team for their kind support.
KUSHAGRA PUNDEER
ICAS, Manipal University
MECHANICAL
4. INDEX
Bharat Heavy Electrical Plant Brief
Quality Policies
Research and Development
WTM Block
Bay 1
Bay 2
Governor Assembly
Bay 3
Bay 4
Bay 5
Bay 6
Bay 7
Bay 8
Hydro Turbines
Classification of Impulse and Reaction Turbine
Francis Turbine
Pelton Turbine
Kaplan Turbine
Hydro Turbine Governor
Spiral case and Stay Ring
Wicket Gate and Operating Mechanism
Construction of Runner Hub and Blade
Power of Water Turbine
Design and Application
Parts manufactured for current projects
Conclusion
5. Bharat Heavy Electrical Plant It is the largest engineering and
manufacturing enterprise in India, both in energy and infrastructure. It is
located at about 7 km from Bhopal railway station and about 18 km from
Airport. With technical assistance from AssociatedElectricals (India) Ltd, a
UK based company it came into existence on 29th
of August, 1956.Pt.
Jawaharlal Nehru dedicated this plant to the nation on 6th
November 1960.
BHEL Bhopal manufactures Hydro, Steam, Marine & Nuclear Turbines;
Heat Exchangers; Hydro & Turbo Generators; Transformers;Switchgears;
Control gears; Transportation Equipment; Capacitor; Bushings; Electric
Motors and Rectifiers.
BHEL Bhopal has its own Laboratories for material testing and instrument
calibration which are accredited with ISO 17025 byNABL. The Hydro
Laboratory, Ultra High Voltage laboratory and Centre for Electric
Transportation are the only laboratories of its kind in this part of the world.
Bharat Heavy Electricals Limited is country’s ‘Navratna’ company and has
earned its place among very prestigious national and international
companies.It finds place among the top class companies of the world for
manufacture of electrical equipment. BHEL caters to core sectors of the
Indian Economyviz., Power Generation's & Transmission,Industry,
Transportation, Telecommunication,Renewable Energy, Defense,etc.
The Company today enjoys national and international presence featuring in
the “Fortune International-500” and is ranked among the top 10 companies
in the world, manufacturing power generation equipment. BHEL is the only
PSU among the 12 Indian companies to figure in “ForbesAsia Fabulous
50” list.
BHEL has:-
· Installed equipment for over 100000 MW of power generation--- for
utilities captive and industrial users.
· Supplied over 225000MVA transformer capacity and other equipment
operating in transmission and distribution network up to 400 kV (AC & DC).
· Supplied over 25000 motors with drive control systems to power projects,
petrochemicals,refineries,steel,aluminum, fertilizers, cement plants etc.
· Supplied Traction electrics and AC/DC locos to power over 12000 km
railway network. Supplied over one million valves to power plants and other
Industries
6.
7. QUALITY POLICIES
Towards meeting its Quality Policy, BHEL is using the vehicle of Quality
Management Systems,which are certified to ISO 9001:2000series of
Standards by Internationally acclaimed certifying agency, BVQI. Corporate
Quality and Unit level Quality structure enables requisite planning, control
and implementation of Companywide Quality Policy and Objectives which
are linked to the Company's Vision statement. Corporate Quality derives
strength from direct reporting to Chairman and Managing Director of the
Company.
Other than traditional Quality functions, today the focus is on:-
· Propagating Quality Management Systems and Total Quality
Management.
· Formulating, implementing and monitoring, "Improvement Plans" with
focus on internal and external Customer Satisfaction.
· Investigations and preventive actions on Critical Quality Issues.
Calibration and testing laboratories of BHEL are accredited under the
National AccreditationBoard for Calibration and Testing Laboratories
(NABL) scheme of Laboratory Accreditation, which has got mutual
recognition with Asia Pacific Laboratory AccreditationConference and
International Laboratory Accreditation Conference.As a result of its thrust
on quality and technology, BHEL enjoys national and international
recognition in the form of Product Certification by International Bodies like
ASME, API and Plant Approvals by agencies like Lloyds Registerof
Shipping, U.K., Chief Controller of Explosives India, TUV Germany etc.
In its movementtowards Business Excellence and with the objective of
achieving International level of Quality, BHEL has adopted European
Foundation for Quality Management (EFQM) modelfor Business
Excellence.Through this modeland annual self-assessmentexercise,
BHEL is institutionalizing continuous improvementin all its operations.
8. RESEARCH AND DEVELOPMENT
To remain competitive and meet customers' expectations, BHEL lays great
emphasis on the continuous improvement of products and related
technologies,and developmentof new products.BHEL's commitment to
advancement of technology is reflected in its involvement in the
development of futuristic technologies like fuel cells and superconducting
generators.
BHEL's investment in R&D is amongst the largest in the corporate sectorin
India. During the year 2010-11,BHEL invested Rs.10050 Million on R&D
efforts-21% higher than the previous year. R&D and technology
developmentare of strategic importance to BHEL as it operates in a
competitive environment where technologyis a key driver. Technology
developmentefforts undertaken by BHEL have led to the filing of patents
and copyrights at the rate of nearly one a day, significantly enhancing the
company's intellectual capital. In 2010-11,BHEL filed 303 patents and
copyrights,enhancing the company's intellectual capital to 1,438 patents
and copyrights filed,which are in productive use in the company's
business.The year saw a massive growth in grant of patents and
copyrights.A total of 91 patents and copyrights were granted during the
year.
Currently, 532 patents & copyrights are in force.Notably, BHEL has been
ranked as the Number One Company in India in terms of filing of patents by
the Economic Times Intelligence Group. Significantly, BHEL is one of the
only four Indian companies and the only Indian Public Sector Enterprise
figuring in 'The Global Innovation 1000' of Booz& Co., a list of 1,000
publicly-traded companies which are the biggestspenders on R&D in the
world.
BHEL has also won the coveted CII-ThompsonReuters Innovation Award
2010 in the 'Hi-tech Corporate' category.The award recognizes BHEL's
innovation and entrepreneurship in India based on number of patents and
efficiencyand impact of innovation as measured by patent citations.
The company's Corporate R&D division at Hyderabad leads BHEL's
research efforts in a number of areas of importance to BHEL's product
range. Researchand ProductDevelopment(RPD)centers at all its
manufacturing divisions play a complementaryrole. BHEL has introduced,
9. in the recent past, several state of the art products.Commercializationof
products and systems developedby way of in-house Researchand
Developmentcontributed Rs.77,580 Million corresponding to around 18%
to the company's total turnover in 2010-11.In keeping with the National
commitmentto a clean environment, BHEL has developed the technology
for Integrated Gasification Combined Cycle (IGCC) power plants and is
pursuing the development of Advance Ultra Supercritical Thermal Power
Plants in the country. BHEL is also actively working on a number of
projects in futuristic areas like Clean Coal Technology,Nano Technology,
Fuel Cells, Superconductivity and thin film solar cells,etc. to advance the
developmentof technologies for power and industry sector.The
engineering and technology character of the organization will be further
enhanced with increased focus on innovation and R&D.
10. WTM BLOCK
Water turbine manufacturing block (block-1)is one of the biggestblocks in
the BHEL complex.Hydro turbine and its associated components are
machined and manufactured here.
The entire block is divided into differentbays.
BAY-1
It houses the following machines:
Deep drilling machine - Used to drill holes in the shaft.
CNC lathe– ComputerNumerically Controlled Lathes
11. Planing machine-uses linear relative motion between the work
piece and a single-pointcutting tool to machine a linear tool path.
Horizontalfloor boring machine-boresholes in horizontal direction.
Verticalboring machine-work piece rotates around a vertical axis.
12. CNC verticalboring machine-ComputerNumerically Controlled
vertical boring machine.
Radial drilling machines-are known for their precision,accuracy
and efficiency.These are designed to meetthe most exacting
requirements of engineering and allied operations and utility. They
ensure smooth rotation of column and avoid angular deflectionof
spindle axis.
Slotting machine-for perfectslotting and planning of materials.
13. Components machined:-
Shaft
Log for lever
Sleeve
Bush housing
Guide bent stock
Hexagonal screw head
Guiding piece
Bush housing
BAY-2
It houses the following machines:
Verticalboringmachine
Table planing machine
Lathe machine
CNC end milling machine
CNC horizontaltable borer
Make-Craven
Boring spindle diameter-130mm
Maximum load capacity-12 tons
Horizontalboring machine
Spindle diameter-88.9mm
Swiveling table size-1067*1067mm
Sliding table size-1676*1067mm
Maximum facing head mill face-1219mm
CNC lathe machine
Components machined:
Rubberseal clamping ring
Bottom cover plate
Bush
Guide vane
Extensiontube
Deflector
14. GOVERNOR ASSEMBLY-Bay2 also houses the governor assemblyarea.
Governor Assembly WTM
Components Manufactured:
Guide Bearing
MIV Servo Motor
Nozzle Assembly-Nozzle tip
15. Anti-Vacuum Valve
Pressure Receiver
By pass valve
BAY-3
It houses the following machines:
Vertical boringmachine
Table diameter-6705mm
Maximum job diameter-7696mm
Maximum capacity-90 tons
CNC verticalboring machine
Runner blade turningmachine
Maximum length of work-8000mm
Maximum diameter that can be turned-4000mm
Length of job that can be done-7200mm
16. Column boringmachine
Table diameter-5523mm
Maximum external diameter that can be machined-9000mm
Stroke of RAM-3353mm
Maximum capacity-100 tons
Componentsmachined:
· Top cover
· Inner turbine housing
· Spacer flange
· Pivoted ring cover
· Sealing flange
· Stay ring
· Runner blade
BAY-4
It houses the following machines:
Lathe machine
CNC lathe machine
Table planing machine
End milling machine
Distance between columns-4242mm
Maximum under bridge movement-3276mm
Maximum length of machines-9144mm
Maximum height up to vertical head-3200mm
Maximum capacity-100 tons
17. Horizontalboring and milling machine
Spindle diameter-203mm
Traverse X-8992mm,Y-4500mm,Z-1981mm
Minimum height of spindle center to bed-760mm
Breaklathe machine
Sliding bed and center height-1422mm
Base plate and center height-2108mm
Saddles rotation over sliding bed-2286mm
Distance between centre-7621mm
Length of sliding bed-9905mm
Diameter of face plate-2438mm
Weightcapacity-50 tons
Verticalmilling machine
Height between spindle nose and table-660mm
Spindle to face column-559mm
Slotting machine
Maximum stroke -530mm
Minimum stroke -190mm
Radialdrilling machine
Verticalboringmachine
18. CNC horizontalfloor borer
Boring spindle diameter-200mm
Column guide way-1050mm
Headstockvertical movement-5000mm
Spindle / rack movement-2000/1600mm
Rotary table size-3150*3150mm
Components machined:
Trunnion
Sleeve screw
Bottom sleeve
Top cover
FABRICATION SHOP
BAY-5
It is the place where degreasing and fabrication work takes place. It houses
the following machines:
Electro slag welding machine
Job completed inone pass
for job of thickness 40-110mm single nose is used
for job of thickness greater than 110mm double nose is used
lesserdefectsas compared to manual arc welding
19.
Oven
heating fuel-LPG
Maximum heating temperature-150 degree Celsius
Maximum size-W-5250mm
Transformertank assembly-H-5000mm
Components fabricated:
Distributor
Pivot ring
Transformertank
BAY-6
It houses the following machines and equipment:
Manualarc welding
Manualgrinding
Submergedarc welding
20. BAY-7
It houses the following machines:
Submergedarc welding
Robotic arm welding
Shot blast plant-Used fortreating corroded parts
Paint shop-Used to paint shot blasted components
Components fabricated:
Transformertank
Spacerflange
Bay-8
It houses the heat exchanger and coolerassembly. Following machines are
situated in this bay:
Lahardeep gun drilling machine
Radialdrilling machine
Arboga CNC drilling machine
Multi-spindle drilling machine
Traverse x-7000mm y-8500mm z-350mm
No. of spindles-8
Min. pitch-100mm
Max.pitch-200mm
per spindle drilling capacity-40mm
Spindle speed-71-1400RPM
Spindle feed-10-1000 mm/min
No. of drilling motors-2
21. Lathe machine
Components machined:
Buffel
Tube plate
Sleeve
PRODUCT INFORMATION
HYDRO TURBINES:-
1. HYDROELECTRIC POWER PLANT:
The purpose of a hydro-electric power plant is to harness power from
water. As such it incorporates a no. of water driven prime movers
known as water turbines. The water or hydraulic Turbine converts the
kinetic and potential energies possessed by water into mechanical
power. The hydraulic turbine when coupled to a generator produces
electric power.
2. Advantages of hydraulic electric power:
a. Cheap and immune to inflation
b. inexhaustible
c. This can be developed wherever water continuously flowing under
pressure.
d. robust, reliable, lest maintenance.
e. Operate in high efficiencylevel.
f. Quick loading and off-loading flexibilities.
g. Idealpeaking partner of base load thermal/nuclear.
h. Multipurpose benefits
i. No pollution to environment.
22. 3. INTRODUCTION:
Hydraulic turbines are highest efficiencyprime movers used for
power productionwhich utilize the energy of water ways. The
hydraulic energy contained in the stream is converted by to mechanical
power.
Basically these are of two types:
a. Impulse turbines
b. Reaction turbines
In an impulse turbine the water possessing kinetic energy is supplied to
the runner at Atmospheric pressure.The flow through the runner is entirely
at atmospheric pressure,the force exerted by the water being due to the
impulse of the jet.
In a reaction turbine the water supplied to the runner possesses energy
which is partly kinetic and partly pressure.Both types of energies are
converted into work in the runner which results in a drop of pressure and
absolute velocity of water.
23. FURTHER CLASSIFICATIONOF IMPULSE AND REACTION
TURBINES:
Impulse turbine:
- pelton turbine
Reaction turbine:
- Francis turbine
- Kaplan and Propellerturbine
Propellerturbines are mainly Kaplan turbines but Moody, nagler and
Bell turbines may be found in market. The main difference between
Kaplan and other type of propellerturbines is that the formerhas
adjusted runner blades.
FRANCIS TURBINE-
These are inward flow reaction turbine.
Used when operating head is in the range of 30-500m.
These are medium pressure turbine.
Total machines -190
Megawatt capacity-5-165 MW
Runner radius-1050-5250mm
24. FRANCIS TURBINES
The Francis turbine is a type of water turbine that was developed by James B.
Francis in Lowell, Massachusetts. It is an inward-flow reaction turbine that combines
radial and axial flow concepts.
The Francis turbine is a reaction turbine, which means that the working fluid changes
pressure as it moves through the turbine, giving up its energy. A casement is needed to
contain the water flow. The turbine is located between the high-pressure water source
and the low-pressure water exit, usually at the base of a dam.
The inlet is spiral shaped. Guide vanes direct the water tangentially to the turbine wheel,
known as a runner. This radial flow acts on the runner's vanes, causing the runner to
spin. The guide vanes (or wicket gate) may be adjustable to allow efficient turbine
operation for a range of water flow conditions.
25. As the water moves through the runner, it’s spinning radius decreases,
further acting on the runner. For an analogy, imagine swinging a ball on a
string around in a circle; if the string is pulled short, the ball spins faster due
to the conservation of angular momentum. This property,in addition to the
water's pressure,helps Francis and other inward-flow turbines harness
water energy efficiently.
At the exit, water acts on cup-shaped runner features, leaving with no swirl
and very little kinetic or potential energy. The turbine's exit tube is shaped
to help decelerate the water flow and recover the pressure.
26. MAIN COMPONENTS OF FRANCIS TURBINE:
1. SPIRAL CASING: in order to distribute the water around the guide
ring evenly the scrollcasing is designed with a cross sectional
area reducing uniformly around the circumference,maximum at
the entrance and nearly zero at tip. This gives spiral shape and
hence is named as spiral casing. These are also provided with
inspectionholes and also with pressure gauge connection.
2. GUIDE MECHANISM: these have a cross sectional area of aero
foil section. This particular cross sectionallows water to pass over
them without forming eddies and with minimum frictional losses.It
is mounted on a ring which is connected to generator shaft by
means of a regulating shaft depending upon load, speed of turbine
is controlled by a governor which basically deals with the guide
vane opening.
3. DRAFT TUBE: It is a conduit which connects the runner exit to the
Tail race. A tube should be drowned approx. below the lowest tail
race level. It basically increases the workable head of turbine by
an amount equal to the height of the runner outlet, thus making it
possibleto install the turbine above the tail race level without loss
of head.
APPLICATION OF FRANCIS TURBINES
Francis turbines may be designed fora wide range of heads and flows.
This, along with their high efficiency,has made them the most widely used
turbine in the world. Francis type units cover a head range from 20 to
700 meters, and their output power varies from just a few kilowatts up to
one Giga watt. Large Francis turbines are individually designed foreach
site to operate at the highest possible efficiency,typically over 90%.
In addition to electrical production, they may also be used for pumped
storage, where a reservoir is filled by the turbine (acting as a pump) during
low power demand, and then reversed and used to generate power during
peak demand.
27. Construction of spherical valve
Valve disc of spherical valve Spherical valve with dismantling joint
Spherical valve under pressure test Construction of spherical valve
PELTON TURBINE
These are impulse turbines which extract energy from the
impulse (momentum) of moving water.
These are high pressure turbines
Total machines-46
Head limit-245-1025m
Megawatt limit-1.5-200 MW
28. The Pelton wheel is an impulse turbine which is among the most efficient
types of water turbines. It was invented by LesterAllan Pelton in the 1870s.
The Pelton wheel extracts energy from the impulse (momentum) of moving
water, as opposed to its weight like traditional overshot water
wheel. Pelton's paddle geometrywas designed so that when the rim runs
at ½ the speed of the water jet, the water leaves the wheel with very little
speed,extracting almost all of its energy, and allowing for a very efficient
turbine.
The water flows along the tangent to the path of the runner. Nozzles direct
forcefulstreams of water against a series of spoon-shaped buckets
mounted around the edge of a wheel. As water flows into the bucket, the
direction of the water velocity changes to follow the contour of the bucket.
When the water-jet contacts the bucket, the water exerts pressure on the
bucket and the water is decelerated as it does a "U-turn" and flows out the
other side of the bucket at low velocity. In the process,the water's
29. momentum is transferred to the turbine. This "impulse" does work on the
turbine. For maximum power and efficiency,the turbine system is designed
such that the water-jet velocity is twice the velocity of the bucket. A very
small percentage of the water's original kinetic energy will still remain in the
water; however, this allows the bucket to be emptied at the same rate it is
filled, (see conservation of mass), thus allowing the water flow to continue
uninterrupted. Often two buckets are mounted side-by-side,thus splitting
the water jet in half (see photo). This balances the side-load forces on the
wheel, and helps to ensure smooth, efficientmomentum transfer of the fluid
jet to the turbine wheel.
Because water and most liquids are nearly incompressible,almostall of the
available energy is extracted in the first stage of the hydraulic turbine.
Therefore,Peltonwheels have only one turbine stage, unlike gas turbines
that operate with compressiblefluid.
PARTS OF PELTONTURBINE:
1. Guide mechanism: this mechanism controls the quality of water
passing through the nozzle and striking the bucket thus meeting
the variable demand of power. It maintains the speed constant of
wheel, when head varies.
2. Bucketand runner: Each bucket is divided vertically into two
parts by splitter, which is the sharp edge at center giving the
shape of double hemispherical cup (in BHEL, the edge of splitter is
cut to increase efficiencyand to reduce the impact force of the
impinging jet which otherwise will decrease the life of bucket).
3. Casing: itdoes not have any hydraulic function to perform.It is
necessaryonly to prevent splashing and to lead the water to tail
race, and also further safe guard against accidents.
4. Hydraulic brakes: Aftershutting down the inlet valve of turbine,
the large capacity of runner will go on revolving or a considerable
period,due to inertia. This has necessitated the developmentof
brakes to bring the turbine to a standstill in a shortestpossible
time.
30. APPLICATION OF PELTON WHEEL
Pelton wheels are the preferred turbine for hydro-power, when the available
water source has relatively high hydraulic head at low flow rates. Pelton
wheels are made in all sizes. There exist multi-ton Pelton wheels mounted
on vertical oil pad bearings in hydroelectric plants. The largest units can be
up to 200 megawatts. The smallest Pelton wheels are only a few inches
across,and can be used to tap power from mountain streams having flows
of a few gallons per minute. Some of these systems utilize
household plumbing fixtures for water delivery. These small units are
recommended foruse with thirty meters or more of head, in order to
generate significant power levels. Depending on water flow and design,
Pelton wheels operate bestwith heads from 15 meters to 1,800 meters,
although there is no theoretical limit.
The Pelton wheel is most efficientin high head applications (see the
"DesignRules" section).Thus, more power can be extracted from a water
source with high-pressure and low-flow than from a source with low-
pressure and high-flow, even when the two flows theoretically contain the
same power. Also a comparable amount of pipe material is required for
each of the two sources,one requiring a long thin pipe, and the other a
short wide pipe.
KAPLAN TURBINE-
The Kaplan turbine is a propeller-type water turbine which has
adjustable blades.
These are reaction turbines
The head ranges from 10-70 meters
Output from 5 to 120 MW
Runner diameters are between 2 and 8 meters
Used in high-flow, low-head power production
31. The Kaplan turbine is a propeller-type water turbine which has adjustable
blades.It was developed in 1913 by the Austrian professor Viktor Kaplan,
who combined automatically adjusted propellerblades with automatically
adjusted wicket gates to achieve efficiencyover a wide range of flow
and water level.
Its invention allowed efficientpower production in low-head applications
that was not possible with Francis turbines. The head ranges from 10-70
meters and the output from 5 to 120 MW. Runner diameters are between 2
and 8 meters.The range of the turbine is from 79 to 429 rpm. Kaplan
32. turbines are now widely used throughout the world in high-flow, low-head
power production.
THEORY OF OPERATION
The Kaplan turbine is an inward flow reaction turbine, which means that the
working fluid changes pressure as it moves through the turbine and gives
up its energy. Power is recovered from both the hydrostatic head and from
the kinetic energy of the flowing water. The designcombines features of
radial and axial turbines.
The inlet is a scroll-shaped tube that wraps around the turbine's wicket
gate. Water is directed tangentially through the wicket gate and spirals on
to a propellershaped runner, causing it to spin.
The outlet is a specially shaped draft tube that helps decelerate the water
and recover kinetic energy.
The turbine does not need to be at the lowest point of water flow as long as
the draft tube remains full of water. A higher turbine location, however,
increases the suction that is imparted on the turbine blades by the draft
tube. The resulting pressure drop may lead to cavitation.
APPLICATION OF KAPLAN
Kaplan turbines are widely used throughout the world for electrical power
production. They cover the lowest head hydro sites and are especially
suited for high flow conditions.
HYDRO TURBINE GOVERNOR
Used to govern the speed of rotation of the runner such that the
frequencyof power generated is 50 Hz.
This is done by controlling the opening of guide vanes.
33. SPIRAL CASE AND STAY RING
Spiral case for turbine with 411m head Stay ring for turbine with 146m head
WICKET GATES AND OPERATING MECHANISM
Wicket gates for a low head turbine Wicket gates for a high head turbine
Wicket gates operating linkage Self-lubricated bearing for wicket gate stem
34. CONSTRUCTION OF RUNNER HUB AND BLADE
The runner blades are operated to smoothly adjust their blade angles by a
link mechanism. Their mechanism is installed inside the runner hub,
containing the runner blade and stem, the link crosshead and so on. A high
quality lubricating oil is filled inside the runner hub to lubricate the
mechanism interior.
Shop assembly of runner Runner blade under machining
MAIN SHAFT
The main shaft for the turbine is made of high-grade forged carbonsteel.
When the size of the main shaft exceeds the limitation of forging capacity
or transportation or it is economical,the main shaft is formed by welding
steel plates or a combination of forged steel and steelplates.
The main shaft is connected to the generator shaft or the intermediate shaft
by a flange coupling. The shaft surface passing through the shaft seal is
protected with a stainless steel shaft sleeve to prevent the main shaft
from wearing.
Forged shaft Fabricated shaft
35. Power of Water Turbine
The power available in a stream of water is;
where:
P = power (J/s or watts)
η = turbine efficiency
ρ = density of water (kg/m³)
g = acceleration of gravity (9.81 m/s²)
h = head (m). For still water, this is the difference in height between the inlet and outlet surfaces.
Moving water has an additional component added to account for the kinetic energy of the flow.
The total head equals the pressure head plus velocity head.
= flow rate (m³/s)
DESIGN AND APPLICATION
Turbine selectionis based mostly on the available water head, and less so
on the available flow rate. In general, impulse turbines are used for high
head sites, and reaction turbines are used for low head sites. Kaplan
turbines with adjustable blade pitch are well-adapted to wide ranges of flow
or head conditions,since their peak efficiencycan be achieved over a wide
range of flow conditions.
36. Small turbines (mostly fewer than 10 MW) may have horizontal shafts and
even fairly large bulb-type turbines up to 100 MW or so may be horizontal.
Very large Francis and Kaplan machines usually have vertical shafts
because this makes best use of the available head, and makes installation
of a generator more economical.Pelton wheels may be either vertical or
horizontal shaft machines because the size of the machine is so much less
than the available head. Some impulse turbines use multiple water jets per
runner to increase specificspeedand balance shaft thrust.
Typical range of heads
• Hydraulic wheelturbine
• Archimedes' screw turbine
• Kaplan
• Francis
• Pelton
• Turgo
0.2 < H < 4
1 < H < 10
2 < H < 40
10 < H < 350
50 < H < 1300
50 < H < 250
Specific speed
The specific speed ns of a turbine characterize the turbine's shape in a way
that is not related to its size. This allows a new turbine designto be scaled
from an existing designof known performance.The specificspeedis also
the main criteria for matching a specific hydro site with the correctturbine
type.
The specific speed is the speed with which the turbine turns for a particular
discharge Q, with unit head and thereby is able to produce unit power.
Affinity laws
Affinity Laws allow the output of a turbine to be predicted based on model
tests. A miniature replica of a proposed design, about one foot(0.3 m) in
diameter, can be tested and the laboratory measurements applied to the
final application with high confidence.Affinity laws are derived by requiring
similitude between the test modeland the application. Flow through the
turbine is controlled either by a large valve or by wicket gates arranged
around the outside of the turbine runner. Differential head and flow can be
plotted for a number of differentvalues of gate opening, producing a hill
diagram used to show the efficiencyof the turbine at varying conditions.
37. Runaway speed
The runawayspeedof a water turbine is its speed atfull flow, and no shaft
load. The turbine will be designed to survive the mechanical forces of this
speed.The manufacturer will supply the runaway speed rating.
Parts manufactured for Current Projects:
Part manufactured Forged Runner
Project AD Hydro Power Ltd.
Wt. of the Part 9200kg
No. of Cups 20
Part manufactured Main Injector
Project Tapovan Vishnugad HEP
Wt. of the part 4900kg
Part manufactured Runner Hub
Project Pulichintala Project
Wt. of Part 9240kg
Part manufactured Door (Francis Turbine)
Project Parbati HEP Stage 3
Wt. of part 32000kg
Part manufactured Runner Blade
Project Pulinchintala Project
Wt. of Part 3779kg
38. CONLUSION
The Vocational training at BHEL Bhopal helped me in
improving my practical knowledge and understanding of
Hydro turbine, its manufacturing and types to a large
extent. Here I came to know about the technology and
material used in manufacturing of hydro turbine. Besides
this, I also visualized the parts involved and equipment
that were used during the manufacturing process of these
turbines. In all it was a truly learning experience for me. As
a mechanical engineering student I hope that the training I
got here would help me in coming future. I hereby thank all
the authorities at BHEL for their kind cooperation and
guidance.