• We classify as turbo-machines all those devices in which energy is
transferred either to or from, a continuously flowing fluid by the
dynamic action of one or more moving blade rows the word turbo or
turbines is of Latin origin and implies that which spins or whirls
• Essentially, a rotating blade row or rotor changes the stagnation
enthalpy of the fluid moving through it by either doing positive
(compressors & pumps) or negative work (turbines), depending upon
the effect required of the machine. These enthalpy changes are
intimately linked with the pressure changes occurring simultaneously
in the fluid.
Turbines, compressors and fans are all members of the same family of
machines called turbo-machines.
A turbo-machine is a power or heat-generating machine, which
employs the dynamic action of a rotating element, the rotor; the action
of the rotor changes the energy level of the continuously flowing fluid
through the turbo-machine.
Two main categories of turbo-machine are identified:
• Absorb power to increase the fluid pressure or head (ducted fans,
compressors and pumps).
• Produce power by expanding fluid to a lower pressure or head
(hydraulic, steam and gas turbines).
Types of Turbines
Hydraulic Gas Turbine Steam Turbine
• A water turbine is a rotary engine that takes energy from moving
• Flowing water is directed on to the blades of a turbine runner,
creating a force on the blades.
• Since the runner is spinning, the force acts through a distance (force
acting through a distance is the definition of work).
• In this way, energy is transferred from the water flow to the turbine.
• Used to generate electricity from the energy of water.
• A gas turbine, also called a combustion turbine, is a type of
internal combustion engine. It has an upstream rotating compressor
coupled to a downstream turbine, and a combustion chamber in-between.
• The compressor, which draws air into the engine, pressurizes it, and
feeds it to the combustion chamber at speeds of hundreds of miles
• The combustion system, typically made up of a ring of fuel
injectors that inject a steady stream of fuel into combustion chambers
where it mixes with the air. The mixture is burned at temperatures of
more than 2000 degrees F. The combustion produces a high
temperature, high pressure gas stream that enters and expands
through the turbine section.
• The turbine is an intricate array of alternate stationary and rotating
aerofoil-section blades. As hot combustion gas expands through the
turbine, it spins the rotating blades.
• The rotating blades perform a dual function they drive the
compressor to draw more pressurized air into the combustion
section, and they spin a generator to produce electricity.
• This high-temperature high-pressure gas enters a turbine, where it
expands down to the exhaust pressure, producing a shaft work output
in the process.
• The turbine shaft work is used to drive the compressor and other
devices such as an electric generator that may be coupled to the
• The energy that is not used for shaft work comes out in the exhaust gases,
so these have either a high temperature or a high velocity.
• these gases can sometimes be used directly, they are more often passed to a
heat recovery boiler for the production of hot water or steam. Where the
site’s heat requirement exceeds the heat available in the exhaust gases, or is
variable, a burner can be incorporated in the ducting between the turbine
and the heat recovery boiler to increase the temperature of the exhaust
gases and improve the heat output of the plant.
• Gas turbines are used to power aircraft, trains, ships, electrical generators,
or even tanks
• Gas turbines accept most commercial fuels, such as petrol, natural gas,
propane, diesel, and kerosene as well as renewable fuels such as biodiesel
• Gas turbine, may be spinning at 100,000 to 500,000 rpm.
• In an ideal gas turbine, gases undergo three thermodynamic processes:
1. an isentropic compression,
2. an isobaric (constant pressure) combustion
3. an isentropic expansion.
Together, these make up the Brayton cycle.
• In a practical gas turbine, mechanical energy is irreversibly transformed
into heat when gases are compressed (in either a centrifugal or axial
compressor), due to internal friction and turbulence.
• Passage through the combustion chamber, where heat is added and the
specific volume of the gases increases, is accompanied by a slight loss in
pressure. During expansion amidst the stator and rotor blades of the
turbine, irreversible energy transformation once again occurs
• Ideal Brayton cycle:
1. isentropic process - ambient air is drawn into the compressor,
where it is pressurized.
2. isobaric process - the compressed air then runs through a
combustion chamber, where fuel is burned, heating that air—a
constant-pressure process, since the chamber is open to flow in and
3. isentropic process - the heated, pressurized air then gives up its
energy, expanding through a turbine (or series of turbines). Some of
the work extracted by the turbine is used to drive the compressor.
4. isobaric process - heat rejection (in the atmosphere).
What's Steam Turbine?
• The steam turbine is a prime mover in which the potential energy of
steam is transformed into kinetic energy and the latter in its turn is
transformed into the mechanical energy of rotation of the turbine
• The turbine shaft, directly, or with the help of a reduction gearing, is
connected with the driven mechanism which can be generator or a
The simplest single-disc steam turbine consists of the following
• Disc with moving blades
• Fixed blades on its periphery.
• Expansion nozzle.
• The shaft along with the disc mounted upon it comprises the most
important part of the turbine and is known as the rotor, which is
housed in the turbine casing.
• The journals of the shaft are placed in bearings, which are located in
the base of the turbine casing
Theory of Working:
• In turbines of these types the expansion of the steam is achieved from its
initial pressure to its final one in a single nozzle or a group of nozzles
situated in the turbine stator and placed in front of the blades of the rotating
• The decrease of steam pressure in the nozzles is accompanied by a
decrease of its heat content; this decrease of heat content achieved in the
nozzles subsequently accounts for the increase in the velocity of the steam
issuing from the nozzles.
• The energy velocity of the steam jets exerts an impulse force on the blades
and performs mechanical work on the shaft of the turbine rotor.
• Process 1-2: The working fluid is pumped from low to high pressure. As the fluid
is a liquid at this stage, the pump requires little input energy.
• Process 2-3: The high pressure liquid enters a boiler where it is heated at constant
pressure by an external heat source to become a dry saturated vapour.
• Process 3-4: The dry saturated vapour expands through a turbine, generating
power. This decreases the temperature and pressure of the vapour, and some
condensation may occur. The output in this process can be easily calculated using
the Enthalpy-entropy chart or the steam tables.
• Process 4-1: The wet vapour then enters a condenser where it is condensed at a
constant pressure to become a saturated liquid.
• In an ideal Rankine cycle the pump and turbine would be isentropic, i.e., the pump
and turbine would generate no entropy and hence maximize the net work output.
Processes 1-2 and 3-4 would be represented by vertical lines on the T-S
diagram and more closely resemble that of the Carnot cycle.
• Rankine cycle shown here prevents the vapor ending up in the superheat region
after the expansion in the turbine, which reduces the energy removed by the
• An ideal Rankine cycle operates between pressures of 30 kPa and 6
MPa. The temperature of the steam at the inlet of the turbine is
550°C. Find the net work for the cycle and the thermal efficiency.
• Wnet=Wturbine-Wpump OR Qin-Qout
• Thermal efficiency hth=Wnet/Qin
• Net work done is converted into power output of turbine.
Steam Turbines Classification
Way of energy
conversion & type of
Axial Flow turbine
• The great majority of turbines, especially those of high power are
• In such turbines the steam flows in direction parallel to the axis of
the shaft leaves the turbine in the same direction.
• The most preferred turbine for electricity generation as several
cylinders can be coupled together to achieve a turbine with greater
• In a radial flow turbine the steam enters the turbine in the direction
of its radius and leaves it in the direction of the axis of the shaft.
• Not preferred for electricity generation and employed for small
outputs such as driving pumps.
Way of Energy Conversion
1) way of energy
- impulse turbines
- reaction turbines
Types of Blade
• The heat energy contained within the steam that passes through a
turbine must be converted into mechanical energy to achieve this
depends on the shape of the turbine blades. The two basic blade
• Impulse working on the principle of high pressure steam hitting
against moving blades.
• Pressure drop only occurs at the nozzles in the turbine.
• In an impulse turbine, the fluid is forced to hit the turbine at high
speed (due to change of potential energy to kinetic energy at the
• They are generally installed in the higher pressure sections of the
turbine where the specific volume of steam is low.
• Blades are usually symmetrical have entrance and exit angles 20.
• Blades are short and have constant cross section area.
PRESSURE-VELOCITY DIAGRAM FOR A TURBINE NOZZLE
HIGH THERMAL ENERGY
LOW THERMAL ENERGY
PRESSURE-VELOCITY DIAGRAM FOR A MOVING IMPULSE BLADE
DIRECTION OF SPIN
PRESSURE-VELOCITY DIAGRAM FOR A MOVING REACTION BLADE
DIRECTION OF SPIN
• The principle of pure reaction turbine is that all energy stored within
the steam is converted to mechanical energy by reaction of the jet of
steam as it expands at the blades of the rotor.
• In a reaction turbine the steam expands when passing across fixed
blades where pressure drop occurs and velocity increase.
• When passing to moving blades both pressure and velocity decreases
occurs in both fixed
and rotating blades.
into kinetic energy
in both stationary
and moving blades
There is change in
both pressure and
velocity as the
through the moving
drop occurs at the
Whole enthalpy is
kinetic energy in
There is no change
in the pressure of
the steam as it
passes through the
There is change
only in the velocity
of the steam flow.
• An impulse stage consists of
stationary blades forming nozzles
through which steam expands,
increasing velocity as a result of
• The steam then strikes the rotating
blades and performs work on them,
which in turn decreases velocity
(kinetic energy)of the steam.
• The steam then passes through
another set of stationery blades
which turn it back to original
direction and increases the velocity
again through nozzle action.
• In the reaction turbine both the
moving and fixed blades are
designed to act like nozzles.
• As steam passes through the
non-moving blades, no work is
exerted pressure will decrease
and velocity will increase.
• In the moving blades are
designed to act like nozzles
velocity and pressure will
decrease due to wok being
extracted from the steam.
Way of compounding
• Compounding of steam turbines is the method in which energy
from the steam is extracted in a number of stages rather than a single
stage in a turbine.
• A compounded steam turbine has multiple stages i.e. it has more than
one set of nozzles and rotors, in series, keyed to the shaft or fixed to
the casing, so that either the steam pressure or the jet velocity is
absorbed by the turbine in number of stages.
• The steam produced in the boiler has very high enthalpy. In all
turbines the blade velocity is directly proportional to the velocity of
the steam passing over the blade.
Why it’s required ?
• Now, if the entire energy of the steam is extracted in one stage, i.e. if the
steam is expanded from the boiler pressure to the condenser pressure in a
single stage, then its velocity will be very high.
• Hence the velocity of the rotor (to which the blades are keyed) can reach to
about 30,000 rpm, which is pretty high for practical uses because of very
• Moreover at such high speeds the centrifugal forces are immense, which
can damage the structure. Hence, compounding is needed.
• The high velocity which is used for impulse turbine just strikes on single
ring of rotor that cause wastage of steam ranges 10% to 12%. To overcome
the wastage of steam compounding of steam turbine is used.
Pressure Compounding impulse turbine
• The pressure compounded Impulse turbine is also called as Rateau turbine,
after its inventor. This is used to solve the problem of high blade velocity
in the single-stage impulse turbine.
• It consists of alternate rings of nozzles and turbine blades. The nozzles are
fitted to the casing and the blades are keyed to the turbine shaft.
• In this type of compounding the steam is expanded in a number of stages,
instead of just one (nozzle) in the velocity compounding. It is done by the
fixed blades which act as nozzles. The steam expands equally in all rows of
• The steam coming from the boiler is fed to the first set of fixed blades i.e.
the nozzle ring. The steam is partially expanded in the nozzle ring. Hence,
there is a partial decrease in pressure of the incoming steam. This leads to
an increase in the velocity of the steam. Therefore the pressure decreases
and velocity increases partially in the nozzle.
Pressure Compounding impulse turbine
• This is then passed over the set of moving blades. As the steam flows
over the moving blades nearly all its velocity is absorbed. However,
the pressure remains constant during this process.
• After this it is passed into the nozzle ring and is again partially
expanded. Then it is fed into the next set of moving blades, and this
process is repeated until the condenser pressure is reached.
• It is a three stage pressure compounded impulse turbine. Each stage
consists of one ring of fixed blades, which act as nozzles, and one
ring of moving blades. As shown in the figure pressure drop takes
place in the nozzles and is distributed in many stage
Velocity Compounding impulse turbine
• The velocity compounded Impulse turbine was first proposed by C G Curtis to solve the
problem of single stage Impulse turbine for use of high pressure and temperature steam.The
rings of moving blades are separated by rings of fixed blades. The moving blades are keyed
to the turbine shaft and the fixed blades are fixed to the casing. The high pressure steam
coming from the boiler is expanded in the nozzle first. The Nozzle converts the pressure
energy of the steam into kinetic energy. It is interesting to note that the total enthalpy drop
and hence the pressure drop occurs in the nozzle. Hence, the pressure thereafter remains
• This high velocity steam is directed on to the first set (ring) of moving blades. As the steam
flows over the blades, due the shape of the blades, it imparts some of its momentum to the
blades and losses some velocity. Only a part of the high kinetic energy is absorbed by these
blades. The remainder is exhausted on to the next ring of fixed blade.
• The function of the fixed blades is to redirect the steam leaving from the first ring moving
blades to the second ring of moving blades. There is no change in the velocity of the steam
as it passes through the fixed blades. The steam then enters the next ring of moving blades;
this process is repeated until practically all the energy of the steam has been absorbed.
Pressure-Velocity compounded Impulse Turbine
• It is a combination of the above two types of compounding. The total pressure drop of the
steam is divided into a number of stages. Each stage consists of rings of fixed and moving
blades. Each set of rings of moving blades is separated by a single ring of fixed blades. In
each stage there is one ring of fixed blades and 3-4 rings of moving blades. Each stage acts
as a velocity compounded impulse turbine.
• The fixed blades act as nozzles. The steam coming from the boiler is passed to the first ring
of fixed blades, where it gets partially expanded. The pressure partially decreases and the
velocity rises correspondingly. The velocity is absorbed by the following rings of moving
blades until it reaches the next ring of fixed blades and the whole process is repeated once
1. Condensing Turbine
• In this type of turbine steam with
pressure (42 bar) and temperature (400C)
enters where pressure drop is occurred in
first stage impulse turbine.
• Then expands in reaction turbine and
exhaust with lower pressure than
• The cooling water condenses the steam
turbine exhaust in the condenser creating
the condenser vacuum by using ejector or
small compressor (vacuum pump).
• This type is used to get only mechanical
energy and not to use the exhaust steam
صمام التحكم بكمية جريان البخار
2. Extraction Turbine
• In this turbine steam is withdrawal
from one or tow stages at a certain
pressure for using at plant
processing such as heating also
called (bleeder turbines).
• This type used for having a steam
with a certain pressure to be used
in other process.
صمام التحكم بكمية جريان
سحب البخار من مرحلة وسطية لتلبية متطلبات أخرى
خروج بخار مكثف
3. Backpressure Turbine
• Non condensing turbine which
exhausts it’s steam to industrial
process or facility steam which
used in another process.
البخار المكثف فوق الضغط الجوي
1 ضغط جوي bar >
صمام التحكم بكمية جريان البخار
ريش ثابتة )التوجيهية(
Back Pressure Turbine مخطط توربين بخاري البخار المكثف أعلى من الضغط الجوي
• Reheat turbines are also used
almost exclusively in electrical
• In a reheat turbine, steam flow
exits from a high pressure
section of the turbine and is
returned to the boiler where
additional superheat is added.
• The steam then goes back into
an intermediate pressure
section of the turbine and
continues its expansion.
116MT01 Condensing turbine with a backpressure extraction
steam to drive LP
LP steam to
118MT01 a backpressure turbine charging MP & LP to headers
What is a stage in a steam turbine?
• In an impulse turbine,
the stage is a set of
moving blades behind
• In a reaction turbine,
each row of blades is
called a "stage.
• " A single Curtis stage
may consist of two or
more rows of moving
Number of stages & Inlet Pressure
• Single stage
• High pressure (p>6,5MPa)
• Intermediate pressure(2,5MPa <p<6,5MPa)
• Low-pressure (p<2,5MPa
Steam Turbine Components
• Frame (Base): supports rotor , stator and governor pedestal.
• Shell: consists of casing , nozzles , steam chest and bearings.
• Rotor:consists of HP&MP&LP pressure stage blades , shaft and
governor pedestal components, thrust bearing, journal bearings,
Turing gear and main lube oil systems.
• Governor pedestal: consists of turbine speed governor and protective
As the steam turbine operates under high temperature and speeds high, the material that makes
them rotary axis must be homogeneous and pure of impurities that cause cracks under pressure and
high temperature as the material must be of high hardness and conducting laboratory tests
including examination (Charpy hardness) to make sure of the hardness of metal rotary axis and
makes this axis melting steel in electric oven and then pour molten steel in the mold topic in a
room deflated to ensure that no entry impurities to steel and added to this alloy steels several
metals to increase hardness and resistance to rust and corrosion, including metal * chromium Cr *
nickel and vanadium Ni * Va * Alamuedinom Mo
Turbine Casing TOP Casing
• The Casing of the turbine is simple structure used to minimize
distortion due to temperature changes.
• They are constructed in two parts (Top – Bottom) along a horizontal
joint so that the turbine is easy to open for inspection.
• With the top casing is removed the rotor can also be easily
withdrawn without the interfering with the alignment of the bearings
Turbine Casing Flanges
• One method of joining the top and
bottom of the casing is by using
flanges with machined holes.
• Bolts are inserted into these
machined holes to hold the top and
bottom casing together.
• To prevent leakage from the joint
between the top flange the joint faces
are accurately machined.
• Blade design is extremely important in attaining high turbine
• Blades are milled from stainless steel within strict specifications
for proper strength and corrosion.
• In HP impulse turbine blades are short so they don’t need to
change the cross section. where the length of the blade (Root) to
(Top) does not constitute a significant change for the length of the
rotor disk diameter (Bladed Rotors disk).
• But in case reaction turbine blades are long can reach 1m.
Turbine blade fixing
• Various root fixing shapes have been developed for turbine blading
to suit construction requirements and conditions under which turbine
• The most popular types are
The purpose of nozzles is to expand the high pressure
steam to extract its energy and direct the resulting
steam jets toward the rotating buckets or blades
• The nozzles are made up of many partitions that
have the appearance of airfoils, similar to rotating
• The partitions change the direction of steam flow to
cause it to impinge on the moving blades of the
rotor, as well as to increase the velocity of the flow.
• The partitions are held in place in a disk-like
structure that, together with the partitions, is called a
diaphragm. Figure shows a typical diaphragm.
• The diaphragm fits into circumferential slots in the
turbine shell inside diameter.
• There are labyrinth seals at the inside diameter of
the diaphragm to reduce steam leakage between the
rotor and the diaphragm and seal strips near the
outside diameter to reduce leakage around the
• The steam chest, located on the
forward, upper half of the HP turbine
casing, houses the throttle valve
• This is the area of the turbine where
main steam first enters the main
engine. The throttle valve assembly
regulates the amount of steam
entering the turbine.
• After passing through the throttle
valve, steam enters the nozzle block.
Balancing Piston (dummy chamber)
• All the rotors of pumps, compressors and turbines experience the axial
thrust due to differential pressure between suction /discharge or inlet
• For small machines a thrust bearing, balancing disk are installed on the
rotor to absorb axial loading. for large machines a device called balancing
piston is keyed/shrunk to the rotor at at high pressure rotor end.
• This balance piston is exposed to high pressure on one side and discharge
pressure/low pressure on other side. The rotor thrust is balanced based on
the area provided on either side of balance piston.
• (dynamic Pressure x Area)= force which acts on HP/LP side of the balance
piston keeps the rotor in position and absorbs major portion of axial thrust.
Residual axial loading is absorbed by thrust bearing.
• Wheel chamber in case of steam turbine is a chamber provided on
HP side of balance piston. It is between first stage( Impulse stage )
nozzle and balance piston. For the same load on the turbine, if wheel
chamber pressure increases it indicates turbine fouling.
• Based on wheel chamber pressure and turbine loading, it is possible
to judge turbine fouling, turbine rotor/stator sealing condition,
balance piston sealing condition
• One of the basic purposes of a bearing is to provide a frictionless
environment to support and guide a rotating shaft.
• They typically depend on a regular supply or motor oil for lubrication, too;
without this they can wear down, which over time will usually lead to
• A thrust bearing is a particular type of rotary rolling-element bearing.
Like other bearings they permit rotation between parts, but they are
designed to support a predominately axial load.
• The bearing pressure acts parallel to the shaft axis.
Types of Thrust bearing
1. Thrust ball bearings.
2. Spherical roller thrust bearings.
3. Fluid film thrust bearings.
4. Tapered roller thrust bearings.
• Journal bearings aligns the rotor and it will cushion the radial
• The bearing pressure acts perpendicular to the shaft axis.
Thrust Bearing Journal Bearing
• To prevent the entry of air from the outside to the inside of the
turbine when the steam pressure inside the final stages less than
atmospheric pressure, as in the type of turbine steam condenser
• To prevent the exit of steam from inside the turbine to the outside of
the exit point axis of the rotor from the cover of the turbine when the
steam pressure in the final stages higher than the atmospheric
pressure, as in the turbine above atmospheric pressure and a seal in
this Mechanic (Mechanical cell) in the turbine Small Size.
• In large turbines are used mechanical seal with vapor supplied from
another source pressure is higher than the vapor pressure in the final
• Is an entry vapor pressure and certain temperature on each of the front and end of
the turbine. seal steam may enter only into the front according to turbine type and
• Under the low-load conditions, the L.P end of the turbine will be under the vacuum
of the surface condenser. The vacuum will tend to pull in cold atmospheric air
through the seals along the shaft.
• Cold air will have a detrimental effect on the hot metal of the shaft which can lead
to damage. In order to minimize these problems, a manually controlled supply of
low pressure SEAL steam (about 2 Psi), is piped to a common line feeding the
glands of the machine.
• A power loss is associated with steam leakage or air ingress. Thus, the design of
glands and seals is optimized to reduce any leakage.
• To improve the efficiency of the turbine to get the
highest Power with less quantity of steam where
the steam expands inside the turbine to be up to a
pressure less than atmospheric pressure.
• Because there is a steam ejector nozzles which
drag air and gases inside the condenser lead to
the occurrence of back pressure at the end of the
• Consumption of steam more to maintain the same
power on it, affecting the efficiency of the
E . steam
• A labyrinth seal is a type of mechanical seal that
provides a tortuous path to help prevent leakage.
• An example of such a seal is sometimes found
within a shaft's bearing to help prevent the leakage
of the oil lubricating the bearing.
• A labyrinth seal may be composed of
many grooves that press tightly inside another
axle, or inside a hole, so that the fluid has to pass
through a long and difficult path to escape.
Stage LABYRINTH Seal
• As well as the type of sealant used to labyrinth seal between
the stage and the next, and put on the barrier between the two
stages where it very close to the rotary axis to prevent leakage of
steam between the rotor axis.
• Where it forces the steam to pass through diaphragms between
blades in order to increase turbine efficiency
• Enters to the turbine front between seal steam and turbine shaft
• To prevent seal steam from entering or it’s condensate to the shaft
bearings and the lube oil may contaminate.
Unit 116 Condenser
• Used to condense the low pressure steam exhaust from the turbine in
order to recycle this condensate back to boiler
Unit 116 Vacuum System
• Vacuum system is used to condense the steam which was not
condensed in the condenser by decreasing the pressure in the
condenser and also decreasing pressure in Low pressure chamber to
increase turbine efficiency.
• It consists of (Ejector – common condenser)
• A steam ejector, is a type of pump that uses the Venturi effect of
a converging-diverging nozzle to convert the pressure energy of a motive
fluid to velocity energy which creates a low pressure zone that draws in
and entrains a suction fluid.
• After passing through the throat of the injector, the mixed fluid expands
and the velocity is reduced which results in recompressing the mixed fluids
by converting velocity energy back into pressure energy.
• The motive fluid may be a liquid, steam or any other gas. The entrained
suction fluid may be a gas, a liquid, a slurry, or a dust-laden gas stream.
• The adjacent diagram depicts a typical modern ejector. It consists of a
motive fluid inlet nozzle and a converging-diverging outlet
nozzle.Water, air, steam, or any other fluid at high pressure provides the
motive force at the inlet.
البخار المسحوب من المكثف
HP Steam Vapors from
• A device to control the turbine to adjust the speed chosen by the
operator despite the change of load increase it or decrease it is
designed on different designs (mechanical, hydraulic, hydraulic /
electronic, electrical / electronic).
• And this device to control the amount of steam flowing from the
valve turbine (main steam control valve) and the by changing its
opening, and there governor last for speeding (Over
Speed Governor) intervenes when increasing the speed of the turbine
suddenly to more than (10%) of the speed controlled to shut off the
steam inlet valve.
• And get this case when there is a defect in the performance of work
which makes it a speed governor is unable to control the turbine
• Hydraulic oil controlling system by control oil
ويكون مساره lube oil الخاص بدائره ال PCV من قبل oil pump • وهو يبدأ من طرد
وذلك لتعويض اى خلل لحظى فى دائره زيت التحكم accumulator • يوجد عليه
• Then divided into Four section
1. To CPC (Current to pressure Converter)
2. Seal steam XV
3. Safety block then to Main steam valve XV
4. To Control valve
ويتكون من Control Oil ان الجزء من هذه الدوائر الذى يخص نظام التحكم هو
Wood Ward حاكم السرعه
( I / H ) •محول الطاقه حيث انه يحول اشاره كهربيه الى ضغط زيت
وهو ينقسم الى Actuator •مشغل بلف التحكم
Oil Relay ) ب servo Motor ) ا
وهو ياخذ الاشاره الكهربيه بقيمه السرعه المطلوبه ويقارنها بالسرعه الفعليه
(I/H) وينتج منها اشاره كهربيه معينه بالزياده او النقصان ويرسلها الى
(I/H) CPC المحول
فياخذ الاشاره من p1 (control oil) يدخل الى المحول نوعين من الزيت
مع هذه الاشاره ويرسله p ويحولها الى ضغط زيت مناسب يسمى 3 W.W
الى مشغل بلف التحكم
الخاص بمشغل بلف التحكم بازحه العمود لبلف التحكم servo motor يقوم ال
المرسله اليه وبالتالى p ا ا زحه تتناسب مع ضغط الزيت 3 (Control valve)
يتم التحكم فى سرعه التربينه
Work Of Speed Governor
اشارة كهربيه بقيمة السرعه المطلوبه
بناءا علي الاشاره الكهربيه يتم خفض ضعط زيت
P التحكم الداخل اليه الي 3
Control valve arrangement
Closing spring V2 + V3
Control valves V1 - V3 Actuator
Spindle packing seals live
steam pressure of valve
chest towards atmosphere
#3 #2 #1
spring V2 + V3
control valve بلف التحكم
التى يمر البخار من خلالها الى الى ريش التربينه وهذه البوابات لها نظام اى ان nozzles ويتكون من بوابتين او ثلاث بوابات متصله بمجموعه من
عند الحمل المنخفض فى بدايه التشغيل throttling لايفتح البلف )البوابه( الثانى الا اذا فتح البلف الذى قبله بالكامل وهذا لتلافى حدوث عمليه
servo motor - مشغل بلف التحكم
الذى يضغط على مكبس التشغيل ويدفعها فى اتجاه فتح بلف التحكم p وهو عباره عن ياى ومكبس تشغيل ويوجد به فتحه لدخول زيت 1
هو عباره عن مكبس ترحيل وياى oil relay -
•فكره عمل بلف التحكم
ويدخل ايضا orifice عن طريق ال servo motor الى p يتم اداخال الزيت 1
p حركه مناسبه لسد فتحه ا رجع الزيت 0 Relay لتحريك p طبقا للاشاره المناسبه من حاكم السرعه فيدخل 3 p ضغط زيت 3
بالانخفاض يتحرك مكبس الترحيل p وعندما يتغير ضغط 3 C.V وبالتالى يتحرك مكبس الترحيل فى اتجاه فتح بلف S.M الداخل ال p مما يؤدى الى زياده ضغط 1
عن طريق قوى الياى . C.V وبالتالى يتحرك مكبس التشغيل فى اتجاه غلق S.M زيت التحكم الداخل الى p لفتح ا رجع الزيت مما يقلل من ضغط 1
Servo Motor Oil Relay
Emergency Stop Valve بلف ايقاف الطوارئ
تكون بلوف العزل الموجوده على خط البخار الرئيسى تكون عاده بلوف يدويه ويكون تشغيل
ويوجد به ذ ا رع توصيل لنقل القوى التى تقوم بفتح وغلق البلفوبين عمود التوصيل وجسم البلف الذى يتحرك servo motor اج ا زء الفتح والغلق بها اما يدويه او عن طريق
خلاله عمود التوصيل هناك مانع تسريب ويكون عليه حشو ولكن بتك ا رر الفتح والغلق يتعرض الحشو للتلف وبالتالى لايؤدى عمله
فى ظروف امنه وخاصه عندما يكون عمود التوصيل معرض لعوامل جويه غير ملائمه من اتربه ورطوبه وايضا فى حلات الطوارئ يلزم عزل البخار عن التربينه بسرعه
لتامين الماكينه trip system لنتمكن من ايقافها فى حلات ال
لذلك وضع بلف ايقاف الطوارئ لان .
هذا البلف ليست به اج ا زء ميكانيكيه معرضه للجو اى انه يعمل عن طريق الوسط المحيط
لان القوى اللازمه للفتح S.M به وفى هذه الحاله يكون الوسط هو البخار لذلك لايوجد به
والغلق تنتج من ضغط الوسط والياى .
يعمل هيدروكليا (pilot control device) ويوجد معه جهاز محكم مساعد
ويلزم فىعمليه فتح وغلق البلف ايقاف الطوارئ
Main cone Pilot cone
Lifting of guide-blade carrier
Removal of turbine rotor and
guide-blade carrier bottom
Scope of Major Overhaul
Operation and maintenance
• When warming up a steam turbine for use, the main steam stop
valves (after the boiler) have a bypass line to allow superheated
steam to slowly bypass the valve and proceed to heat up the lines in
the system along with the steam turbine.
• Also, a turning gear is engaged when there is no steam to the turbine
to slowly rotate the turbine to ensure even heating to prevent uneven
• After first rotating the turbine by the turning gear, allowing time for
the rotor to assume a straight plane (no bowing), then the turning
gear is disengaged and steam is admitted to the turbine, first to the
astern blades then to the ahead blades slowly rotating the turbine at
10–15 RPM (0.17–0.25 Hz) to slowly warm the turbine.
• Any imbalance of the rotor can lead to vibration, which in extreme
cases can lead to a blade breaking away from the rotor at high
velocity and being ejected directly through the casing. To minimize
risk it is essential that the turbine be very well balanced and turned
with dry steam - that is, superheated steam with a minimal liquid
• If water gets into the steam and is blasted onto the blades (moisture
carry over), rapid impingement and erosion of the blades can occur
leading to imbalance and catastrophic failure. Also, water entering
the blades will result in the destruction of the thrust bearing for the