The document summarizes several thermodynamic cycles including the Otto, Diesel, Carnot, refrigeration, and Brayton cycles. For each cycle, it outlines the key processes and applications. The Otto cycle involves two isentropic and two constant volume processes and is used in spark ignition engines. The Diesel cycle uses constant pressure heat addition and has a higher efficiency than the Otto cycle. The Carnot cycle involves reversible, isothermal and adiabatic processes and sets the maximum possible efficiency. The refrigeration cycle uses vapor compression to transfer heat between regions. The Brayton cycle consists of adiabatic compression and expansion with isobaric heat transfer and is commonly used in gas turbine engines.

1. DEPARTMENT OF MECHANICAL
ENGINEERING

2. Presented by Group No 09

3. Presented by Zain ul Abdeen

4. First four-stroke engine was patented by Alphonse Beau de Rochas
in 1861.
First working four-stroke engine was built by German engineer
Nikolaus Otto.
Otto Cycle consist of two isentropic processes and two constant
volume processes.
 It is an idealized cycle that describes functioning of spark ignition
engines.
Commonly used in automobile engines

5. Processes:
1-2 Isentropic Compression Stroke.
2-3 Ignition/Heat In Ignition Phase.
3-4 Isentropic Expansion Stroke.
4-1 Heat Rejection Phase.

6. Presented by Gulshair

7. Invented by Rudolph Diesel in 1893.
Also known as constant pressure cycle.
high thermal efficiency and compression ratio (11:1 to 22:1)as
compared with Otto cycle
Diesel is used as fuel in this cycle.
 Diesel cycle is used where more power is needed with less amount
of fuel.
 Mainly used in two stroke and 4 stroke diesel engines.

8. Processes
The 4 process are as follows:
Isentropic (reversible adiabatic) Compression
Constant pressure heat addition
Isentropic Expansion
Constant volume heat rejection

10. Presented by Noman Asghar

11.  Proposed by Nicolas Léonard Sadi Carnot in 1824.
 It is an ideal or imaginary cycle.
 It is a reversible cycle.
 ∆𝑆 = 0
 The Carnot cycle is composed of four reversible processes:
1. Isothermal Expansion
2. Adiabatic Expansion
3. Isothermal Compression
4. Adiabatic Compression

12. Isothermal Expansion Adiabatic Expansion Isothermal Compression Adiabatic compression

13.  Carnots theorem: No engine operating
between two heat reservoirs can be more
efficient than a Carnot engine operating
between those same reservoirs.
 Efficiency of carnot cycle:
𝑛 = 1 −
𝑇𝐶
𝑇 𝐻
 But Efficiency of heat engine always < 100%
 Heat cannot be completely converted into 100%
work in a cyclic process.
 From here search for second law begins.

15. • A major application area of thermodynamics is refrigeration, which
is the transfer of heat from a lower temperature region to a higher
temperature one. Devices that produce refrigeration are called
refrigerators, and the cycles on which they operate are called
refrigeration cycles.

16. The most frequently used refrigeration cycle
is the vapor-compression refrigeration cycle
in which the refrigerant is vaporized and
condensed alternately and is compressed in
the vapor phase.
The vapor-compression refrigeration cycle
has four components: evaporator,
compressor, condenser, and expansion (or
throttle) valve.

17. The ideal vapor-compression cycle
consists of four processes.
1-2 Isentropic compression
2-3 Constant pressure heat rejection
in the condenser
3-4 Throttling in an expansion valve
4-1 Constant pressure heat addition
in the evaporator

18. Presented by Azeem Sarwar

19. Brayton cycle is named after George Brayton whose describes
working of heat engines.
The original Brayton engine used a piston compressor and piston
expander.
It was constant pressure two-stroke engine.
 A Brayton engine consists of three components: a compressor, a
mixing chamber and expander.

20. 1-2 Adiabatic Process – Compression
2-3 Isobaric Process – Heat Addition
3-4 Adiabatic Process – Expansion
4-1 Isobaric Process – Heat Rejection

21.  Thermodynamics, an engineering approach by YUNUS A. ÇENGEL and
MICHAEL A. BOLES 8th edition
 https://www.youtube.com/watch?v=2s-zQZ93Lu8
 wikipedia