Steam turbine and its types
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Transcript of Steam turbine and its types
APPLIED MECHANICAL ENGINEERING
STEAM TURBINESH ighly Mechanized!
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APPLIED MECHANICAL ENGINEERING
TABLE OF CONTENTS
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INTRODUCTION
We’ll learn in this presentation:
WORKING PRINCIPLE
CLASSIFICATION
WORK DONE & EFFICIENCY
APPLIED MECHANICAL ENGINEERING
INTRODUCTION
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Under this head, we’ll discuss:
DEFINATION1
ACTION OF STEAM2
ADVANTAGES OF STAM TURBINES OVER R. STEAM ENGINES
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APPLIED MECHANICAL ENGINEERING
DEFINATION
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A prime mover in which rotatory motion is obtained by the gradual change of momentum of the steam
‘‘ ’
’
A machine that transforms energy from thermal, electrical or pressure form to mechanical
form
APPLIED MECHANICAL ENGINEERING
ADVANTAGES OF STEAM TURBINE OVER R. STEAM ENGINE
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SPEED STEAM RANGE
EFFICIE-NCY
STEAM CONSU-MPTION
SAFETY
FRICTIONAL
LOSSAPPLIED TORQUE
REPAIR
COSTSPACE REQUIRED
APPLIED MECHANICAL ENGINEERING
ADVANTAGES OF STEAM TURBINES OVER R. STEAM ENGINES
3
SPEED & STEAM RANGE
EFFICIE-NCY
STEAM CONSUM
-PTIONSAFETY
FRICTION-AL LOSS
APPLIED TORQUE
ATTENTION & REPAIR
COST
APPLIED MECHANICAL ENGINEERING
WORKING PRINCIPLE
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Under this head, we’ll discuss:
GENERAL PARTS1
PRINCIPLE OF ACTION2
APPLIED MECHANICAL ENGINEERING
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SAFETY
APPLIED MECHANICAL ENGINEERING
GENERAL PARTS OF STEAM TURBINE
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NOZZLE
Heat energy of the high pressure steam is converted into kinetic energy
BLADES
Change direction of steam issuing from the nozzle
APPLIED MECHANICAL ENGINEERING
The generation of high velocity steam jet by the expansion of high pressure steam and then conversion of kinetic energy, so obtained into mechanical work on rotor blades.
‘‘
’’
1
PRINCIPLE OF ACTION
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APPLIED MECHANICAL ENGINEERING
ADVANTAGES OF STEAM TURBINES OVER R. STEAM ENGINES
3
SPEED & STEAM RANGE
EFFICIE-NCY
STEAM CONSUM
-PTIONSAFETY
FRICTION-AL LOSS
APPLIED TORQUE
ATTENTION & REPAIR
COST
APPLIED MECHANICAL ENGINEERING
CLASSIFICATION
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BLADE FLOW PASSAGE
The steam turbine are classified on the basis of:
CYLINDER FLOW ARRANGMENT
DIRECTION OF FLOW
NUMBER OF STAGES
APPLICATION OF TURBINE
SPEED OF TURBINE
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APPLIED MECHANICAL ENGINEERING
ADVANTAGES OF STEAM TURBINES OVER R. STEAM ENGINES
3
SPEED & STEAM RANGE
EFFICIE-NCY
STEAM CONSUM
-PTIONSAFETY
FRICTION-AL LOSS
APPLIED TORQUE
ATTENTION & REPAIR
COST
APPLIED MECHANICAL ENGINEERING
ON BASIS OF BLADE FLOW PASSAGE
IMPULSE TURBINE
REACTION TURBINE
*THESE TYPES ARE DISCUSSED IN DETAIL IN LATER SLIDES
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APPLIED MECHANICAL ENGINEERING
ADVANTAGES OF STEAM TURBINES OVER R. STEAM ENGINES
3
SPEED & STEAM RANGE
EFFICIE-NCY
STEAM CONSUM
-PTIONSAFETY
FRICTION-AL LOSS
APPLIED TORQUE
ATTENTION & REPAIR
COST
APPLIED MECHANICAL ENGINEERING
ON BASIS OF CYLINDER FLOW ARRANGMENT
Single cylinder turbines are the one which have all the stages enclosed in one cylinder while in multi cylinder turbines the stages are accommodated in morethan one cylinders, say two or three. Flow in these can be single flow, double flow, cross flow or reversed flow.
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APPLIED MECHANICAL ENGINEERING
ADVANTAGES OF STEAM TURBINES OVER R. STEAM ENGINES
3
SPEED & STEAM RANGE
EFFICIE-NCY
STEAM CONSUM
-PTIONSAFETY
FRICTION-AL LOSS
APPLIED TORQUE
ATTENTION & REPAIR
COST
APPLIED MECHANICAL ENGINEERING
ON BASIS OF DIRECTION OF FLOW
RADIAL FLOW TURBINE
TANGENTIAL FLOW TURBINE
AXIAL FLOW TURBINE
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APPLIED MECHANICAL ENGINEERING
ADVANTAGES OF STEAM TURBINES OVER R. STEAM ENGINES
3
SPEED & STEAM RANGE
EFFICIE-NCY
STEAM CONSUM
-PTIONSAFETY
FRICTION-AL LOSS
APPLIED TORQUE
ATTENTION & REPAIR
COST
APPLIED MECHANICAL ENGINEERING
RADIAL FLOW TURBINE
Radial flow turbine incorporates two shafts end to end and can be
of suitably small sizes.
Radial flow turbines can be started quickly and so well suited for
peak load and used as stand by turbine or peak load turbines.
These are also termed as LJUGSTROM TURBINE.
Radial flow turbines were developed by B.F. Ljungstorm of Sweden
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APPLIED MECHANICAL ENGINEERING
ADVANTAGES OF STEAM TURBINES OVER R. STEAM ENGINES
3
SPEED & STEAM RANGE
EFFICIE-NCY
STEAM CONSUM
-PTIONSAFETY
FRICTION-AL LOSS
APPLIED TORQUE
ATTENTION & REPAIR
COST
APPLIED MECHANICAL ENGINEERING
RADIAL FLOW TURBINE In radial flow turbines the steam is injected in middle near shaft and steam flows radially outwards through the successive moving blades placed concentrically. In radial flow turbines there are no stationary blades so pressure drop occurs in moving blade passage. Concentric moving blades rings are designed to move in opposite directions. 15
APPLIED MECHANICAL ENGINEERING
ADVANTAGES OF STEAM TURBINES OVER R. STEAM ENGINES
3
SPEED & STEAM RANGE
EFFICIE-NCY
STEAM CONSUM
-PTIONSAFETY
FRICTION-AL LOSS
APPLIED TORQUE
ATTENTION & REPAIR
COST
APPLIED MECHANICAL ENGINEERING
TANGENTIAL FLOW TURBINE The steam is the nozzle directs steam
tangentially into buckets at the
periphery of single wheel and steam
reverses back and re-enters other
bucket at its’ periphery.
This is repeated several times as steam
follows the helical path.
Tangential flow turbines are very robust
but less efficient. 16
APPLIED MECHANICAL ENGINEERING
ADVANTAGES OF STEAM TURBINES OVER R. STEAM ENGINES
3
SPEED & STEAM RANGE
EFFICIE-NCY
STEAM CONSUM
-PTIONSAFETY
FRICTION-AL LOSS
APPLIED TORQUE
ATTENTION & REPAIR
COST
APPLIED MECHANICAL ENGINEERING
AXIAL FLOW TURBINE
Steam flows along the axis of turbine
over blades. These axial flow turbines are well suited
for large turbo generators and very
commonly used presently.
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APPLIED MECHANICAL ENGINEERING
ADVANTAGES OF STEAM TURBINES OVER R. STEAM ENGINES
3
SPEED & STEAM RANGE
EFFICIE-NCY
STEAM CONSUM
-PTIONSAFETY
FRICTION-AL LOSS
APPLIED TORQUE
ATTENTION & REPAIR
COST
APPLIED MECHANICAL ENGINEERING
ON BASIS OF NUMBER OF STAGES
SINGLE STAGE TURBINE
MULTI STAGE TURBINE
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APPLIED MECHANICAL ENGINEERING
ADVANTAGES OF STEAM TURBINES OVER R. STEAM ENGINES
3
SPEED & STEAM RANGE
EFFICIE-NCY
STEAM CONSUM
-PTIONSAFETY
FRICTION-AL LOSS
APPLIED TORQUE
ATTENTION & REPAIR
COST
APPLIED MECHANICAL ENGINEERING
ON BASIS OF APPLICATION OF STEAM
CONDENSING TURBINE
PASS OUT TURBINE
NON- CONDENSING TURBINE
BACK PRESSURE TURBINE
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APPLIED MECHANICAL ENGINEERING
ADVANTAGES OF STEAM TURBINES OVER R. STEAM ENGINES
3
SPEED & STEAM RANGE
EFFICIE-NCY
STEAM CONSUM
-PTIONSAFETY
FRICTION-AL LOSS
APPLIED TORQUE
ATTENTION & REPAIR
COST
APPLIED MECHANICAL ENGINEERING
ON BASIS OF SPEED OF TURBINE
LOW SPEED TURBINE
NORMAL SPEED TURBINE
HIGH SPEED TURBINE
>3000 RPM
= 3000 RPM
<3000 RPM 20
APPLIED MECHANICAL ENGINEERING
IMPULSE TURBINE
A turbine which runs by the impulse of steam jet‘
‘ ’’
The force because of change in tangential component of velocity of fluid which may be due to change in direction or magnitude.
The steam is first made to flow through nozzle. Then the steam impinges on the turbine blades. After impinging, steam glides over the concave
surface of the blades and finally, leave the turbine. 21
APPLIED MECHANICAL ENGINEERING
DE-LEVEL IMPULSE TURBINEThe simplest type of impulse turbine & most commonly used.
MAIN COMPONENTS:
1. NOZZLE
2. RUNNER AND BLADES
3. CASING 22
APPLIED MECHANICAL ENGINEERING
MAIN COMPONENTS
NOZZLE
It is a circular guide mechanism. It regulates the flow of steam. It is kept close to the blades, in
order to minimize the losses due
to windage.
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APPLIED MECHANICAL ENGINEERING
MAIN COMPONENTS
RUNNER & BLADES:
These consist of a circular disc fixed
to a horizontal shaft. The steam jet impinges on the buckets,
which move in the direction of the jet. This movement of the blades makes the
runner to rotate. 24
APPLIED MECHANICAL ENGINEERING
MAIN COMPONENTS
CASING:
It is air-tight metallic case, which
contains the turbine runner and blades. It controls the movement of steam
from the blades to the condenser. It is essential to safegaurd the runner
against any accident. 25
APPLIED MECHANICAL ENGINEERING
DE-LEVEL IMPULSE TURBINE
PRESSURE & VELOCITY OF STEAM IN AN IMPULSE TURBINE
The pressure of steam jet is reduced in the nozzle and
remain constant while passing through the moving
blades. The velocity of steam is increased in the nozzle, and is
reduced while passing through the moving blades.
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APPLIED MECHANICAL ENGINEERING
DE-LEVEL IMPULSE TURBINE
PRESSURE & VELOCITY OF STEAM IN AN IMPULSE TURBINE
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APPLIED MECHANICAL ENGINEERING
REACTION TURBINE
MECHANISM
The steam enters through a section
of curved blades in a fixed position. The steam then enters the set of
moving blades and creates enough
reactive force to rotate them. The steam exits the section of
rotating blades. The direction of rotation.
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APPLIED MECHANICAL ENGINEERING
REACTION TURBINE
The water enters the guide case of the turbine with high
potential energy and relatively low kinetic energy.
The potential energy, which is a function of the pressure
difference between the runner inlet and exit, causes the fluid
to flow through the runner buckets.
As the fluid flows over the curved surface of the runner
buckets, the fluid velocity on one side of the bucket is higher
than on the opposite side. 29
APPLIED MECHANICAL ENGINEERING
REACTION TURBINE
This difference in velocity on the surfaces of the bucket causes a
pressure differential across the bucket which exerts a force on
the bucket. This force at its respective radius in the runner, the revolving
part, then causes the runner to restore and impart mechanical
energy to the turbine shaft. 30
APPLIED MECHANICAL ENGINEERING
PARSON’S REACTION TURBINEThe simplest type of reaction turbine & most commonly used.
MAIN COMPONENTS:
1. CASING
2. GUIDE MECHANISM
3. TURBINE RUNNER
4. DRAFT TUBE 31
APPLIED MECHANICAL ENGINEERING
MAIN COMPONENTS
CASING
It is an air-tight metallic case, in which
the steam from the boiler, under high
pressure & temperature. This casing is designed in such a way
that steam enters the fixed blades
with a uniform velocity. 32
APPLIED MECHANICAL ENGINEERING
MAIN COMPONENTS
GUIDE MECHANISM
It is mechanism, made up with the
help of guide blades, in the form of a
wheel. This wheel is, generally fixed to casing;
that is why these guide blades are
called FIXED BLADES. 33
APPLIED MECHANICAL ENGINEERING
MAIN COMPONENTS
GUIDE BLADES
Allow the steam to enter the runner
without shock.
Allow the required quantity of steam
to enter the turbine.
They are properly designed in order to:
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APPLIED MECHANICAL ENGINEERING
MAIN COMPONENTS
TURBINE RUNNER
The turbine runners consists of runner
blades fixed to a shaft or rings.
The surface of the turbine runner is
made smooth to minimize the
frictional looses. 35
APPLIED MECHANICAL ENGINEERING
MAIN COMPONENTS
DRAFT TUBE
The steam, after passing through
runner, flow into the condenser
through a tube called DRAFT TUBE
In case of its absence, steam eddies
are caused. 36
APPLIED MECHANICAL ENGINEERING
PARSON’S REACTION TURBINE
PRESSURE & VELOCITY OF STEAM IN REACTION TURBINE
The pressure in a reaction turbine is reduced in fixed
blades as well as in moving blades. The velocity of steam is increased in the fixed blades
and is reduced while passing through the moving
blades.37
APPLIED MECHANICAL ENGINEERING
PARSON’S REACTION TURBINE
PRESSURE & VELOCITY OF STEAM IN AN IMPULSE TURBINE
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APPLIED MECHANICAL ENGINEERING
COMPARISON
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2
3
4
5
6 39
APPLIED MECHANICAL ENGINEERING
WORK DONE & EFFICIENCY
In order to determine the work done and efficiencyof steam turbine, we’ll consider:
RANKINE CYCLE
Rankine cycle is a thermodynamic cycle derived from Carnot vapour power cycle for overcoming itslimitations.
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APPLIED MECHANICAL ENGINEERING
RANKINE CYCLE
1 - 2ISOBARIC HEAT
SUPPLY 3 - 4ISOBARIC HEAT
REJECTION
2 - 3ADIABATIC EXPANSION 4 - 1
ADIABATIC PUMPING
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APPLIED MECHANICAL ENGINEERING
UNDERSTANDING THE ARRANGMENT
1 - 2High pressure water supplied by feed pump is heated and transformed into steam with or without superheat as per requirement. This high pressure and temperature steam is sent for expansion in steam turbine. Heat added in boiler, for unit mass of steam.
QSUPPLY = (h2 – h1)
Steam available from boiler is sent to steam turbine, where it's adiabatic expansion takes place and positive work is available. Expanded steam is generally found to lie in wet region.
Wturbine = (h2 – h3)
2 - 3
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APPLIED MECHANICAL ENGINEERING
UNDERSTANDING THE ARRANGMENT
Heat rejection process occurs in condenser at constant pressure causing expanded steam to get condensed into saturated liquid at state 4.
Qrejected = (h3 – h4)
Condensate available as saturated liquid at state 4 is sent to feed pump for being pumped back to boiler at state 1.
Wpump = (h1 – h4)
3- 4
4 - 1
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APPLIED MECHANICAL ENGINEERING
3
ANALYTICAL ANALAYSIS
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APPLIED MECHANICAL ENGINEERING
IMPROVEMENT IN ITS EFFICIENCY
REDUCING HEAT ADDITION IN
BIOLER
REDUCING FEED PUMP WORK
INCREASING STEAM TURBINE
EXPANSION WORK
USING HEAT REJECTED AT CONDENSOR
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