Steam formation & Turbines Boiler Classification of boilers Water tube boiler  Fire tube boiler Difference between water tube boiler and fire tube boiler  Applications of boilers Steam formation T-H, T-V & T-S diagrams Specific Volume Enthalpy  Internal Energy Dryness fraction Steam Turbines Impulse Turbine Reaction Turbine Gas Turbines Open cycle gas turbine Closed cycle gas turbine Difference between the Open cycle gas turbine & closed cycle turbine

1. Steam formation &
Turbines
By:
Prof. Siddesh Kumar N M
Assistant Professor
Department of Mechanical Engineering
PES College of Engineering Mandya

2. Boiler
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Prof. Siddesh Kumar N M PESCE Mandya

3. Classification of boilers
• According to content in the tube
• Fire tube boiler
• Water tube boiler
• According to the orientation of boiler
• Horizontal boiler
• Vertical boiler
• According to location of boiler
• Internal boiler
• External boiler
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Prof. Siddesh Kumar N M PESCE Mandya

4. Classification of boilers
• According to method of circulation
• Natural circulation
• Forced circulation
• According to number of tubes
• Single tube boiler
• Multi tube boiler
• According to boiler mobility
• Stationary boiler
• Mobile or portable boiler
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Prof. Siddesh Kumar N M PESCE Mandya

5. Classification of boilers
• According to boiler pressure
• Low pressure boiler
• Medium pressure boiler
• High pressure boiler
• Based on draft used
• Natural draft
• Artificial draft
• Based on fuel used
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Prof. Siddesh Kumar N M PESCE Mandya

6. Water tube
boiler
• Furnace is situated outside
the boiler shell
• Water circulates between the
drum and the tube
• Complete combustion takes
place
• Thermal efficiency is high
• Steam generation is fast
• Easy for cleaning
• High cost
• Used in Power plants
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Prof. Siddesh Kumar N M PESCE Mandya

7. Fire tube
boiler
• Furnace is situated inside the
boiler shell
• Water circulates within the drum
only
• Incomplete combustion takes
place
• Thermal efficiency is low
• Steam generation is slow
• Not Easy for cleaning
• Low cost
• Used in Process industries or
industrial plants
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Prof. Siddesh Kumar N M PESCE Mandya

8. Difference between water tube boiler and fire
tube boiler
Water tube boiler Fire tube boiler
• Furnace is situated outside the boiler shell • Furnace is situated inside the boiler shell
• Water circulates between the drum and the
tube
• Water circulates within the drum only
• Complete combustion takes place • Incomplete combustion takes place
• Thermal efficiency is high • Thermal efficiency is low
• Steam generation is fast • Steam generation is slow
• Easy for cleaning • Not Easy for cleaning
• High cost • Low cost
• Used in Power plants • Used in Process industries or industrial plants
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Prof. Siddesh Kumar N M PESCE Mandya

9. Applications of boilers
• These are used to generate power in steam turbines or
engines.
• These are used for various processes in process industries
• These are used in houses or buildings in cool weather for
generating a hot water supply
• In textile industry for sizing and humidification etc.
• In sugar and chemical industries
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Prof. Siddesh Kumar N M PESCE Mandya

10. Steam
• Steam is the most common working
substance used in steam engines,
steam turbines and atomic power
plants for generation of power
• Steam is the vapor of water and
produced by the application of
thermal energy to the fluid
• Vapor is the intermediate phase
between liquid and gas
• If vapor is superheated then it obeys
gas laws
• The superheated steam is used for
power generation
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Prof. Siddesh Kumar N M PESCE Mandya

11. Steam formation
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Prof. Siddesh Kumar N M PESCE Mandya

12. Steam
formation
Steam is generated by the application of heat
or thermal energy to the water
The heat energy can be obtained from many
sources like coal, oil, gas, solar & nuclear fuels
The heating is done at different pressure and
temperature
Pressure plays an important role in the
generation of the steam
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Prof. Siddesh Kumar N M PESCE Mandya

13. Steam generation can be divided into three
stages
Heating of water up to boiling point Evaporation of boiling water & its
conversion into dry saturated steam
Transformation of dry steam into
super saturated steam
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Prof. Siddesh Kumar N M PESCE Mandya

14. Steam formation
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Prof. Siddesh Kumar N M PESCE Mandya

15. Steam
formation
Generally steam formation is taken place
at constant pressure
Piston weight is applying constant
pressure on water
Vapors are formed by the addition of
heat input
The formation of steam is clearly
understood by T-H, T-V & T-S diagrams
Let us consider 1Kg of water at –10
degree Celsius as the initial point
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16. T-H diagram
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Prof. Siddesh Kumar N M PESCE Mandya

17. T-H diagram
• When heat is added its temperature
raises 0°C (273 K) there fore melting
starts (2 – 3) during this process solid
phase changes to liquid phase
• Entire ice is melted at (3) only liquid
water is present at that point
• Once the temperature becomes
100°C, vapor will start to form (3-4 & 4-
5) both liquid and vapor form will be
present
• Temperature remains constant while
converting (Isothermal process)
• Addtion of heat will cause the super
heating of steam
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Prof. Siddesh Kumar N M PESCE Mandya

18. T-V diagram
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Prof. Siddesh Kumar N M PESCE Mandya

19. T-V diagram
• Latent heat of fusion: Amount of
heat required to convert ice into
water (transformation of phases
from solid to liquid).
• Sensible heat: Amount of heat
required to convert liquid state of
water into vapourization (0 – 100 C
boiling point).
• Saturation temperature:
Temperature at which vaporization
takes places at constant pressure.
• Latent heat of vapourization:
Amount of heat required to
complete transformaton of water
into vapor at constant temperature
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Prof. Siddesh Kumar N M PESCE Mandya

20. P- V diagram
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Prof. Siddesh Kumar N M PESCE Mandya

21. P- V diagram
• Convertion taking places at lower
pressure result in the phase
transformation of soild,
solid+liquid,mixture of liquid
+vapor,and vapor
• Increase in pressure will reduces the
straight horizontal line which results
in the reduction of phase
transformation
• At certain pressure the distance
becomes zero that point is critical
point
• The point at which the liquid phase
will not exit that point we call it as
critical point
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Prof. Siddesh Kumar N M PESCE Mandya

22. P-T diagram
• This is also called as phase
diagram
• All three lines meet at a point
called as triple point
• All three phases co exits at a
point in equilibrium called as
triple point
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Prof. Siddesh Kumar N M PESCE Mandya

23. Specific Volume
• Specific volume of steam can be
defined as the volume occupied by
unit mass of steam at given
temperature & pressure
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Prof. Siddesh Kumar N M PESCE Mandya

24. Enthalpy
Enthalpy of wet steam
• Amount of heat supplied at
constant pressure to convert 1Kg
of water at 0 C to 1Kg of wet
steam at the specified dryness
fraction
Enthalpy of super heated steam
• Amount of heat supplied at
constant pressure to convert 1Kg
of water at 0 C to 1Kg of supper
heated steam at the saturated
temperature
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Prof. Siddesh Kumar N M PESCE Mandya

25. Internal Energy
• It is the actual energy stored in the steam
• The total heat of the steam is sum of all sensible heat, internal latent heat and external work of
evaporation
• Work of evaporation is not stored in the steam as it is utilized in doing the external work
• Internal energy of steam is defined as the difference between entropy of steam and the external
work of evaporation
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Prof. Siddesh Kumar N M PESCE Mandya

26. Dryness fraction
• It is defined as the ratio of mass of
actual dry steam to the total mass
of wet steam containing in it
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28. Steam Turbines
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Prof. Siddesh Kumar N M PESCE Mandya

30. Steam Turbine
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Prof. Siddesh Kumar N M PESCE Mandya

31. Classification of Steam
turbines
Steam turbine can be classified into two types
• Impulse turbine:
• It works on the principle of impulse where kinetic
energy of the force impenges on the blades and
produces force which results in the change in
momentum
• Ex: De laval turbine,curtis turbine
• Reaction turbine:
• It works on the principle of reaction, a reaction force is
developed along with the development of centrifugal
force
• Ex: Parsons turbine
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Prof. Siddesh Kumar N M PESCE Mandya

32. Impulse Turbine
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Prof. Siddesh Kumar N M PESCE Mandya

33. Principle & Operation of Impulse steam turbine
De- Laval Turbine
• The centrifugal force is exerted all
along the curved surfaces
• Centrifugal forces causes the blade to
move
• Rotor is a device in which the blades
are arranged on the circumference of
the wheel
• They will be moved by dynamic action
of the wheel
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Prof. Siddesh Kumar N M PESCE Mandya

34. Impulse Turbine or De
Laval Turbine
• In this turbine steam is initially expanded in nozzle from
high pressure to low pressure
• The high velocity jet of steam coming out of the nozzle is
made to glide over the curved vanes called blade
• The high velocity of steam deflects the blade in
circumferential direction
• This cause the change in motion and momentum
• The change is momentum is caused by centrifugal force
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Prof. Siddesh Kumar N M PESCE Mandya

35. Principle & Operation of reaction
steam turbine
Parsons Turbine
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Prof. Siddesh Kumar N M PESCE Mandya

36. Pressure velocity changes
in Reaction turbine
• High pressure steam passing in the first row causes
small pressure drop and increase in velocity
• When it enters moving blade again suffers from
pressure drop and velocity of steam gets converted
into mechanical energy of rotation
• After conversion the velocity of steam reduces and
this continues
• This continues up to the complete reduction of
pressure of the steam
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Prof. Siddesh Kumar N M PESCE Mandya

37. Reaction turbine (Parsons
Turbine)
• The reaction turbine is also called as Impulse reaction turbine
• Consists of both fixed and moving blades fitted on the
circumference
• Here the high pressure steam does not expand initially in the nozzle
instead passes through moving blades and fixed blades
• The steam experience a nozzle effect in between
• The pressure drop increase simultaneously with increase in velocity
• Along with the force backward reaction takes place thus the sum of
forces acting on the blades are reaction force and centrifugal force
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Prof. Siddesh Kumar N M PESCE Mandya

38. Difference between the Impulse turbine & Reaction turbine
Impulse turbine Reaction turbine
Complete expanssion takes place in
nozzle
Steam expands continuously and
sucessively in bith fixred and moving
blades
Blades are symmetrical in shape Blades are not symmetrical and aerofoil
in shape
Rotor runs at high speed Rotor runs at relativly low speed
Occupies less place per unit power Occupies more space per unit power
Suitabke for small scale power
generation
Suitable for medium and large scale
power generation
Pressure of the steam remains constant
throught the blade
Pressure reduction takes places from
inlet to outlet of the blade
Size of the impuse turbine is less Size of the reaction turbine is more
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Prof. Siddesh Kumar N M PESCE Mandya

39. Gas Turbines
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Prof. Siddesh Kumar N M PESCE Mandya

40. Gas turbines
• Gas turbine is a devices which uses
combust gases to produce mechanical
energy
• Based on the cycle of operation gas turbine
is divied into two types
• Open type gas turbine
• Closed type gas turbine
• Instead of steam here combust gases will
be used
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Prof. Siddesh Kumar N M PESCE Mandya

41. Working Principle of open cycle gas turbine
• IT consists of compressor, combustion
chamber and gas turbine
• Both compress and gas turbine are coupled
and mounted on the same shaft
• The atmospheric air is drawn and
compressed into high pressure
• The high pressure air is drawn into the
combustion chamber and heat is addded
• The high temperature gas is passed into
turbine and expanssion takes place
• The gas after expansion sent into
atmosphere
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Prof. Siddesh Kumar N M PESCE Mandya

42. Working Principle of closed cycle gas turbine
• IT consists of compressor, combustion
chamber, gas turbine and coller
• Both compress and gas turbine are coupled
and mounted on the same shaft
• The atmospheric air is drawn and
compressed into high pressure
• The high pressure air is drawn into the
combustion chamber and heat is addded
• The high temperature gas is passed into
turbine and expanssion takes place
• The gas after expansion sent into cooler,
again it is compressed and sent to
compressor
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Prof. Siddesh Kumar N M PESCE Mandya

43. Difference between the Open cycle gas turbine & closed cycle
turbine
Open cycle gas turbine Closed cycle gas turbine
Working fluid is replacced after every
cycle
Working fluid is replaced after certain
number of cycles
Exhxaut gas is sent to atmosphere Exhaust gas is sent to cooler
Mixture of air and product of
combustion gas is used as a fuel
Any fuel can be used as working
substance
High grade fuels are used to supply of
heat
Any grade fuel is used to supply of heat
There will be heat and mass transfer
takes places
There will be only heat transfer between
system and surroundings
Loss of working substance takes places No loss of working substance
Cooling wate is not required Cooling water is required
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Prof. Siddesh Kumar N M PESCE Mandya

44. Thank You
By:
Prof Siddesh Kumar N M
Assistant Professor
Department of Mechanical
Engineering
PES College of Engineering
Mandya
Mail Id:
siddeshkumarnm@pesce.ac.in
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Prof. Siddesh Kumar N M PESCE Mandya