Steam turbine

1. WATBAN AL- TEKREETI
Submitted by

2. A seminar Report
Submitted by
WATBAN AL- TEKREETI

3. What is the turbine?
What is the principle of steam turbine?
Types of steam turbine.
Component of steam turbine.
Problems in steam turbine.
 Difference –between impulse and reaction turbine

4. 1-A Turbine is a device which converts the heat
energy of steam into the kinetic energy & then to rotational
energy .
1.Introduction

5. 1.2. Definition
A steam turbine is a mechanical device that
extracts thermal energy from pressurized
steam, and converts it into rotary motion.
Main advantages of steam turbines as
propulsion plants are:
- high power
- simple, low weight and compact
propulsion plants
- good manoeuvring abilities
- low request in space for their location
- relatively easy and simple plant maintaining
and
handling

6. Turbine is an engine
that converts energy of
fluid into mechanical
energy
The steam turbine is
steam driven rotary
engine.

7.  The steam energy is converted mechanical work by
expansion through the turbine.
 Expansion takes place through a series of fixed
blades(nozzles) and moving blades.
 In each row fixed blade and moving blade are called
stage.

8. 8
Steam turbine:
• Widely used in CHP(combined heat and power)
applications.
• Oldest prime mover technology
• Capacities: 50 kW to hundreds of MWs
• Thermodynamic cycle is the “Rankin cycle” that
uses a boiler
• Most common types
• Back pressure steam turbine
• Extraction condensing steam turbine
Steam Turbine System:

9. 9
• Steam exits the turbine at a higher pressure that the
atmospheric
Back Pressure Steam Turbine
Fuel
Figure: Back pressure steam turbine
Advantages:
-Simple configuration
-Low capital cost
-Low need of cooling water
-High total efficiency
Disadvantages:
-Larger steam turbine
Boiler Turbine
Process
HP Steam
Condensate LP
Steam
Steam turbine:

10. 10
• Steam obtained by
extraction from an
intermediate stage
• Remaining steam is
exhausted
• Relatively high
capital cost, lower
total efficiency
Extraction Condensing Steam
Turbine
Boiler Turbine
Process
HP Steam
LP Steam
Condensate
Condenser
Fuel
Figure: Extraction condensing steam turbine
Steam turbine:

11. steam turbine and blades

12.  There are two main types
1. Impulse steam turbine
2. Reaction steam turbine

13.  The basic idea of an impulse turbine is that a jet
of steam from a fixed nozzle pushes against the
rotor blades and impels them forward.
 The velocity of steam is twice as fast as the
velocity of blade.
 Pressure drops take place in the fixed blade
(nozzle).

14.  The turbine consists of a single rotor to which
impulse blades are attached.
 The steam is fed through one or several
convergent nozzles.
 If high velocity of steam is allowed to flow
through one row of moving blades.
 It produces a rotor speed of about 30000 rpm
which is too high for practical use.

17.  Main components are
1. Casing
2. Rotor
3. Blades
4. Stop and control valve
5. Oil befell, steam befell
6. governor
7. Bearing(general and thrust bearing)
8. Gear box(epicyclic gear box)
9. Oil pumps

18. 1 – steam pipeline
2 – inlet control valve
3 – nozzle chamber
4 – nozzle-box
5 – outlet
6 – stator
7 – blade carrier
8 – casing
9 – rotor disc
10 – rotor
11 – journal bearing
13 – thrust bearing
14 – generator rotor
15 – coupling
16 – labyrinth packing
19 – steam bleeding (extraction)
21 – bearing pedestal
22 – safety governor
23 – main oil pump
24 – centrifugal governor
25 – turning gear
29 – control stage impulse blading

19.  A reaction turbine utilizes a jet of steam that
flows from a nozzle on the rotor.
 Actually, the steam is directed into the
moving blades by fixed blades designed to
expand the steam.
 The result is a small increase in velocity over
that of the moving blades.

22.  Stress corrosion carking
 Corrosion fatigue
 Pitting
 Oil lubrication
 imbalance of the rotor can lead to vibration
 misalignment
 Thermal fatigue

23.  Unknown 26%
 Stress-Corrosion Cracking 22%
 High-Cycle Fatigue 20%
 Corrosion-Fatigue Cracking 7%
 Temperature Creep Rupture 6%
 Low-Cycle Fatigue 5%
 Corrosion 4%
 Other causes 10%

24.  Resultant damage:
 Extensive pitting of airfoils, shrouds, covers,
blade root surfaces.
 Causes of failure:
 Chemical attack from corrosive elements in
the steam provided to the turbine.

25.  Resultant damage:
 Airfoils, shrouds, covers permanently
deformed.
 Causes of failure:
 Deformed parts subjected to steam
temperatures in excess of design limits.

26.  Resultant damage:
 Cracks in airfoils, shrouds, covers, blade
roots.
 Causes of failure:
 Loosing of parts (cover, tie wire, etc.)
 Exceeded part fatigue life design limit

27.  Resultant damage:
 Cracks in highly stressed areas of the
blading.
 Causes of failure:
 caused by the combined presence of
corrosive elements and high stresses in
highly loaded locations.

29.  Steam turbines operate at silent and quiet conditions.
 They develop high powers and enable high speeds for
large vessels.
 Because of high costs of fuel they do not have wider
application on board (in merchant - flag marine)
 In case of navy, there is practically a rule, that any
larger vessel is powered by steam turbine, because the
diesel engine can not follow the turbine characteristics.
.

30. http://www.ehow.com/how_7218252_calculate-power-output-
steam-turbine.html
http://www.energy.siemens.com/hq/en/services/power-
generation/performance-enhancement/steam-turbine.htm
http://www.ori.milano.it/admin/tmp/files/Sito/turbine%20marine
Introduction to marine engineering, D. A. Taylor, Elsevier Ltd,
1996