Power Generation

1. Selection of Materials and Shape for Strong &
Enduring Non-Biological Muscles ……
P M V Subbarao
Professor
Mechanical Engineering Department
I I T Delhi
Turbines for Steam Power Plants

2. Development of A Sustainable Non-
Biological Beast
• The steam Power Plant is the largest non-biological beast .
• Needs an elaborate anatomy for efficient conversion of chemical
energy into Mechanical/Electrical energy.
• The working fluid is the blood of this animal.
• The pump is the heart of this beast & cyclically induces life into
the working fluid.
• The steam generator is the digestion system of this beast.
• The steam turbine is the Muscle system of this beast.
• The supercritical steam turbines are the strongest and most
efficient non-biological muscles.
• An essential requirement for human development.

3. KE is Like ATP

4. Power Plant Steam Turbines
A Two Step Conversion of Microscopic
Kinetic Power to Shaft Power…….

5. High Pressure
High MKE Steam System
Shaft power to generator
Dead Steam
Dead must be properly recycled

6. Thermodynamic Validation of Flowing
Steam Work
Work is said to be done by a system i
the sole effect external to the syste
can be reduced to raising of weight
Ve
Ub
Vi
Steam with
High KE
Negligible MKE
Drop in KE
Increase in MLE
Low KE
Low MLE

7. The Steam Turbine
• The more modern device to extract shaft power from Microscopic
kinetic Power is the steam turbine.
• Steam turbines have been the norm in various land based power
plants for more than 100 years.
• Turbine is a flow device develops a variable pressure form inlet
to outlet.
• A flowing steam performs work transfer, while moving from high
inlet pressure (Live Steam) to low outlet pressure (Dead Steam).
• The volume of steam continuously increases during this process.
• The infinitesimal work done by a flowing fluid is defined as
Vdp
W 




dead
Live
p
p
out
in Vdp
W
- Sign is important part of this definition.
- Steam flowing in the direction of
decreasing pressure performs +ve work.

8. Continuous Generation of Power
• How to introduce finite mass flow rate of steam?
• Area for Flow of Fluid.
• Proportional to the Length of the Blade.
• More Number of Blade Spacings.

9. Concept of Two Step Conversion :
Kinetic Power to Shaft Ppwer
• Steam turbine is a two part device:
• Part 1:Energy Converter : Nozzles or Stationary Blades
• Part 2: Energy Exchanger: Rotor or Moving Blades.

10. Classification of Rotors or Rotor
Blades
• Single Job Rotors: Only Exchange of Macro Kinetic Power
from steam to Shaft Power via blades.
• Also called as Impulse Blades/rotor.
• Dual Job Rotors: Both energy conversion and Energy
Exchange.
• Known as Reaction Blades/rotor.
• Best choice for Large Power Plant Turbines

11. Nozzle wheel and Blade Wheel

12. U
Vr1
Vr2
Va1
U
Vr1
Va1
Inlet Velocity Triangle
U
Vr2
Va2 Exit Velocity Triangle
Top View of the Steam & Blade Interactions

13. U
Vr1
Va1
Vr2
Va2
b1
a1
a2 b2
Va1: Inlet Absolute Velocity
Vr1: Inlet Relative Velocity
Vr2: Exit Relative Velocity
Va2:Exit Absolute Velocity
a1: Inlet flow Angle.
b1: Inlet Blade Angle.
b2: Exit Blade Angle.
a2: Exit flow Angle.
The Velocity Triangles

14. Vr2
Va2
Ub
Vr1
Va1
b1
a1
a2 b2
Va1: Inlet Absolute Velocity
Vr1: Inlet Relative Velocity
Vr2: Exit Relative Velocity
Va2:Exit Absolute Velocity
a1: Inlet flow Angle.
b1: Inlet Blade Angle.
b2: Exit Blade Angle.
a2: Exit flow Angle.
Selection of The Velocity Triangles

15. Blade Shape

16. Mechanical Arrangements of Steam
Turbines
• The blade velocity is defined at mean diameter of rotor wheel.
• For same wheel speed, the blade velocity is directly
proportional to blade height.
• The height of the blade is proportional to specific volume of
steam.
• Solutions to Turbo-machinery Speed Issues (TSI).
• Tandem Reheat Steam Turbine
• Cross Compound Steam Turbine

17. Tandem Reheat Steam Turbine

18. Cross Compound Reheat Steam Turbine

19. Tandem-compound four-flow steam turbine

20. Large-Capacity Steam Turbines for Fossil
Thermal Power Plant

21. Some Facts about Advanced Steam
Turbines

22. Increased Magnitudes of Forces

23. Steam Volume Variation HP Range
0
0.005
0.01
0.015
0.02
0.025
0.03
0.035
0.04
0.045
0 5 10 15 20 25 30
Steam Path, Mpa
Specific
volume,
m
3
/kg

24. Steam Volume Variation IP Range
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
0.5
0 1 2 3 4 5 6
Steam Path, Mpa
Specific
volume,
m
3
/kg

25. Steam Volume Variation LP Range
0
5
10
15
20
25
30
35
0 0.1 0.2 0.3 0.4 0.5 0.6
Steam Path, Mpa
Specific
volume,
m
3
/kg

26. Bleeding for FWHs : A win-win Idea

27. Power Split between the modules
0.0
5.0
10.0
15.0
20.0
25.0
30.0
35.0
40.0
45.0
50.0
A B C D E
OEM
Percent
of
generated
power
HP
IP
LP

28. Stage Losses & Generation of Entropy

29. High-performance blading : Advanced Aero Design

30. Advanced Blades for ST

31. Modular Concept of Blade Construction

32. Efficiency of USC Turbine Modules:800MW

33. Typical ~ 500 MW Designs

34. Typical ~ 800 MW Designs

35. ~ 1000 MW Designs

36. Major equipment in A Power Plant

37. Exhaust Diffuser For L P Turbine

38. Large Power Plant Condenser