Vapour power cycles

1. VAPOUR POWER
CYCLES
RANKINE CYCLE
III SEM- ENGINEERING THERMODYNAMICS-UNIT IV VAPOUR POWER
CYCLEES/DR.R.SUDHAKARAN
1

2. III SEM- ENGINEERING THERMODYNAMICS-UNIT IV VAPOUR POWER
CYCLEES/DR.R.SUDHAKARAN
2
THEOROTICAL CYCLE ON WHICH STEAM
TURBINE WORKS

3. III SEM- ENGINEERING THERMODYNAMICS-UNIT IV VAPOUR POWER
CYCLEES/DR.R.SUDHAKARAN
3
SCHEMATIC DIAGRAM

4. III SEM- ENGINEERING THERMODYNAMICS-UNIT IV VAPOUR POWER
CYCLEES/DR.R.SUDHAKARAN
4
PROCESSES
Process 1-2 : Reversible adiabatic expansion in the turbine (or steam engine).
Process 2-3 : Constant-pressure transfer of heat in the condenser.
Process 3-4 : Reversible adiabatic pumping process in the feed pump.
Process 4-1 : Constant-pressure transfer of heat in the boiler.

5. III SEM- ENGINEERING THERMODYNAMICS-UNIT IV VAPOUR POWER
CYCLEES/DR.R.SUDHAKARAN
5
4-1 BOILER
STATE OF FLUID
4-WATER
1-STEAM
4
4
1
1
1
1
f
f
h
h
Q
h
Q
h
boiler
for
SFEE





6. III SEM- ENGINEERING THERMODYNAMICS-UNIT IV VAPOUR POWER
CYCLEES/DR.R.SUDHAKARAN
6
1-2 TURBINE
STATE OF FLUID
1-STEAM
2-STEAM
Dryness
reduces
during
expansion
2
1
2
1
h
h
W
W
h
h
Turbine
for
SFEE
T
T





7. III SEM- ENGINEERING THERMODYNAMICS-UNIT IV VAPOUR POWER
CYCLEES/DR.R.SUDHAKARAN
7
2-3 CONDENSOR
STATE OF FLUID
2-STEAM
3-WATER
3
3
2
2
2
2
f
f
h
h
Q
h
Q
h
Condensor
for
SFEE





8. III SEM- ENGINEERING THERMODYNAMICS-UNIT IV VAPOUR POWER
CYCLEES/DR.R.SUDHAKARAN
8
3-4 PUMP
STATE OF FLUID
3-WATER
4-WATER
3
4
4
3
f
f
P
P
f
f
h
h
W
W
h
h
Pump
for
SFEE





9. III SEM- ENGINEERING THERMODYNAMICS-UNIT IV VAPOUR POWER
CYCLEES/DR.R.SUDHAKARAN
9
EFFICIENCY
1
1 Q
W
W
Q
W
cycle
Rankine
of
Efficiency
P
T
NET
RANKINE




)
(
)
(
)
(
4
3
4
1
2
1
1 f
f
f
NET
RANKINE
h
h
h
h
h
h
Q
W
cycle
Rankine
of
Efficiency







)
(
)
(
)
( 3
4
3
4 2
1 f
f
f
f h
h
h
h
as
h
h
Neglect 



)
(
)
(
4
1
2
1
1 f
NET
RANKINE
h
h
h
h
Q
W
cycle
Rankine
of
Efficiency






10. III SEM- ENGINEERING THERMODYNAMICS-UNIT IV VAPOUR POWER
CYCLEES/DR.R.SUDHAKARAN
10
METHODS OF IMPROVING RANKINE EFFICIENCY
Increasing
boiler
pressure
•. It has been
observed that by
increasing the boiler
pressure (other
factors remaining the
same) the cycle
tends to rise and
reaches a maximum
value at a boiler
pressure of about
166 bar
Superheatin
g
•. All other factors
remaining the same,
if the steam is
superheated before
allowing it to expand
the Rankine cycle
efficiency may be
increased. The use of
superheated steam
also ensures longer
turbine blade life
because of the
absence of erosion
from high velocity
water particles that
are suspended in wet
vapour.
Reducing
condenser
pressure.
•The thermal
efficiency of the
cycle can be amply
improved by
reducing the
condenser pressure
(hence by reducing
the temperature at
which heat is
rejected), especially
in high vacuums. But
the increase in
efficiency is obtained
at the increased cost
of condensation
apparatus.

11. III SEM- ENGINEERING THERMODYNAMICS-UNIT IV VAPOUR POWER
CYCLEES/DR.R.SUDHAKARAN
11

12. III SEM- ENGINEERING THERMODYNAMICS-UNIT IV VAPOUR POWER
CYCLEES/DR.R.SUDHAKARAN
12
SCHEMATIC DIAGRAM

13. III SEM- ENGINEERING THERMODYNAMICS-UNIT IV VAPOUR POWER
CYCLEES/DR.R.SUDHAKARAN
13

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CYCLEES/DR.R.SUDHAKARAN
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CYCLEES/DR.R.SUDHAKARAN
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CYCLEES/DR.R.SUDHAKARAN
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CYCLEES/DR.R.SUDHAKARAN
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18. III SEM- ENGINEERING THERMODYNAMICS-UNIT IV VAPOUR POWER
CYCLEES/DR.R.SUDHAKARAN
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SCHEMATIC DIAGRAM

19. III SEM- ENGINEERING THERMODYNAMICS-UNIT IV VAPOUR POWER
CYCLEES/DR.R.SUDHAKARAN
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CYCLEES/DR.R.SUDHAKARAN
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CYCLEES/DR.R.SUDHAKARAN
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CYCLEES/DR.R.SUDHAKARAN
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