Steam engine

1. 15-04-2023 Side 1
Madan Mohan Malaviya Univ. of Technology, Gorakhpur
Steam Engine
Lecture 11
Unit 1
Sunil Kumar Yadav
Assistant Professor
Mechanical Engineering Department
Madan Mohan Malaviya University of Technology
Gorakhpur (UP State Govt. University)
Email: skyme@mmmut.ac.in
Mobile: 9235552353

2. 15-04-2023 Side 2
Madan Mohan Malaviya Univ. of Technology, Gorakhpur
Steam Engine
• Steam engine is an external combustion engine in which
steam is used as the working substance to convert heat
into work.
• The steam generated in the boiler is delivered to the
cylinder of the reciprocating steam engine.
• The steam expands and performs useful work on the
engine shaft.
• The first steam engine was developed by James Watt in
1763 and this led to the era of industrial revolution.

3. 15-04-2023 Side 3
Madan Mohan Malaviya Univ. of Technology, Gorakhpur

4. 15-04-2023 Side 4
Madan Mohan Malaviya Univ. of Technology, Gorakhpur
TYPES OF STEAM ENGINE
• 1. According to the position of cylinder:-
• Horizontal Steam Engine: When axis is horizontal position in steam
engine,it is called horizontal steam engine.
• Vertical Steam Engine: When axis is vertical position in steam
engine,it is called vertical steam engine.
2. According to the number of working stroke:-
• Single Acting Steam Engine: When steam is coming in one side of
the piston and it produces one single working stroke in each
revolution of the crankshaft, is called single acting steam engine.
• Double Acting Steam Engine: When steam is coming in both side of
the piston and it produces double working stroke in each revolution, is
called double acting steam engine. It produces double power than
single acting steam engine.

5. 15-04-2023 Side 5
Madan Mohan Malaviya Univ. of Technology, Gorakhpur
3. According to the number of cylinders in which steam expands:-
• Simple Steam Engine: When expansion of steam is carried out in a
single cylinder, called simple steam engine.
• Compound Steam Engine: When expansion of steam is carried out in
a two or more cylinders, called compound steam engine.
4. According to the type of exhaust:-
• Condensing Steam Engine: When steam is exhausted in a condenser
called condensing steam engine.
• Non-Condensing Steam Engine: When steam is exhausted in the
atmosphere called non-condensing steam engine.
5. According to the field of application:-
• Stationary Engine
• Locomotive Engine
• Marine Engine

6. 15-04-2023 Side 6
Madan Mohan Malaviya Univ. of Technology, Gorakhpur
Double-action steam
engine:
Piston pushed by steam on both
up- and down-stroke.
No more need for a condenser.
Steam is simply vented at high
temperature
slide valve alternates input & exhaust

7. 15-04-2023 Side 7
Madan Mohan Malaviya Univ. of Technology, Gorakhpur
Double-action steam engine
slide valve alternates input &
exhaust

8. 15-04-2023 Side 8
Madan Mohan Malaviya Univ. of Technology, Gorakhpur
Double-action steam engine
What are benefits?
Faster cycle – no need to wait for condensation. Can get more
power, higher rate of doing mechanical work.
Also lighter and smaller – no need to carry a condenser around.
What are drawbacks?
Inefficiency – venting hot steam means you are wasting energy.
High water usage – since lose steam, have to keep replacing the
water

9. 15-04-2023 Side 9
Madan Mohan Malaviya Univ. of Technology, Gorakhpur
Double-action steam engine
primary use: transportation

10. 15-04-2023 Side 10
Madan Mohan Malaviya Univ. of Technology, Gorakhpur
Double-action steam engine:
Images top, left: Sandia Software
Image bottom: Ivan S. Abrams
water-intensive,
fuel-intensive –
requires many
stops to take on
water and fuel.

11. 15-04-2023 Side 11
Madan Mohan Malaviya Univ. of Technology, Gorakhpur
Indicator diagram
• Indicator diagram of steam engine is a graphical representation
which defines with variation in pressure and volume of steam inside
the engine cylinder denotes with PV diagram.
• Assumption for Indicator diagram:
 The steam enters in boiler pressure and released at condenser pressure.
 The opening and closing steam ports are instantaneous.
 Steam is hyperbolic at the time of expansion or compression which is PV=c.
 Steam pressure remains constant at the time of condensation and no wire
drawing due to restricted valve opening.
 The expansion and compression of steam is hyperbolic nature (PV=c).
 But practically all the above points are not possible. so theoretical
indicator diagram of steam engine is slightly different from actual
indicator diagram.

12. 15-04-2023 Side 12
Madan Mohan Malaviya Univ. of Technology, Gorakhpur
Theoretical Indicator Diagram

13. 15-04-2023 Side 13
Madan Mohan Malaviya Univ. of Technology, Gorakhpur
Actual Indicator Diagram

14. 15-04-2023 Side 14
Madan Mohan Malaviya Univ. of Technology, Gorakhpur
Diagram Factor
• The area of the actual indicator diagram is less than the area of the
theoretical indicator diagram.
• The ratio of the areas of these two diagrams is called the diagram factor
or card factor denoted k.
k =

15. 15-04-2023 Side 15
Madan Mohan Malaviya Univ. of Technology, Gorakhpur
The Carnot cycle
• The Carnot cycle, proposed in 1824 by Sadi Carnot, is a
reversible cycle.
• The Carnot cycle consists of four reversible processes
– Two reversible adiabatic processes
– Two reversible isothermal processes
• It can be executed in a closed system or a steady flow mode.
• We shall consider a closed system consisting of a piston-
cylinder arrangement.
• Friction and other irreversibilities are assumed to be absent.
Lect-
14

16. 15-04-2023 Side 16
Madan Mohan Malaviya Univ. of Technology, Gorakhpur
The Carnot cycle
• Reversible isothermal
expansion (1-2)
• Gas allowed to expand
slowly.
• Infinitesimal heat
transfer to keep TH
constant.
• Since temperature
differential never
exceeds dT, reversible
isothermal process.
• Total heat transfer: QH
TH =
constant
QH
Energy
source
at TH
1 2
Process 1-2

17. 15-04-2023 Side 17
Madan Mohan Malaviya Univ. of Technology, Gorakhpur
The Carnot cycle
• Reversible adiabatic
expansion (2-3)
• Insulation at the
cylinder head
• Temperature drops from
TH to TL
• Gas expands and does
work
• Process is therefore
reversible and adiabatic.
TH
3
2
TL
Insulation
Process 2-3

18. 15-04-2023 Side 18
Madan Mohan Malaviya Univ. of Technology, Gorakhpur
The Carnot cycle
• Reversible isothermal
compression (3-4)
• Insulation removed
• TL is constant
• Infinitesimal heat
transfer to the sink at TL
• Temperature differential
never exceeds dT,
reversible isothermal
process
• Total heat transfer: QL
3
4
Energy
sink
at TL
QL
TL =
constant
Process 3-4

19. 15-04-2023 Side 19
Madan Mohan Malaviya Univ. of Technology, Gorakhpur
The Carnot cycle
• Reversible adiabatic
compression (4-1)
• Temperature rises
from TL to TH
• Insulation put back
• The gas is
compressed in a
reversible manner.
• The temperature
rises from TL to TH
TH
1 4
TL
Insulatio
n
Process 4-1

20. 15-04-2023 Side 20
Madan Mohan Malaviya Univ. of Technology, Gorakhpur
The Carnot cycle
• 1-2: A reversible isothermal process
Q1=U2-U1 +W1-2
• 2-3: A reversible adiabatic process
0=U3-U2+W2-3
• 3-4: Reversible isothermal process
Q2=U4-U3-W3-4
• 4-1: Reversible adiabatic process
0=U1-U4-W4-1
Q1-Q2=W1-2+W2-3-(W3-4+W4-1)
Qnet= Wnet for the cycle
Lect-
14

21. 15-04-2023 Side 21
Madan Mohan Malaviya Univ. of Technology, Gorakhpur
The Carnot cycle
V
P
1
3
4
QH
QL
TL=constant
2
TH=constant
Wnet,out
S
T
1 2
3
4
QH
QL
H
T =constant
TL=constant
P-V diagram of Carnot cycle T-S diagram of Carnot cycle

22. 15-04-2023 Side 22
Madan Mohan Malaviya Univ. of Technology, Gorakhpur