CHAPTER ONE INTRODUCTION TO THERMODYNAMICS . . . . . .. . . .

1. SOKOINE UNIVERSITY OF AGRICULTURE
Department of Engineering sciences and Technology
BPE213/AE211 :APPLIED THERMODYNAMICS
A COMPREHESIVE SIMPLIFIED TO THE APPLIED THERMODYNAMICS
2017
Musadoto

2. About the author:
musadoto is a student at Sokoine University Of Agriculture undertaking bachelor of
science in Irrigation and Water Resources engineering 2rd year with full registration number
iwr/d/2016/0011.Samuye and Njombe secondary were his ordinary and advanced education
level respectively.
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3. Forewords
This pamphlet aim to help all engineering students at Sokoine University of Agriculture in
attempting the BPE211/AE213 exams because as curriculum instruct that this kind of course
should an open system.the main aim is to reduce the amount materials in the examination room
that may cause confusion to individual student and time consuming due to dis organization of
material.This pamphlet consists of Ten Topics as given out by the course instructor and atleast
1000 solved questions at which 100 from each Topic.All past papers.tutorials,summaries from
many books are included inside.Dont forget to study carefuly by your own to improve your
understanding .
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4. Acknowledgement
Much thanks to my God who laid all the following;
Bsc .of irrigation and water resources engineering students for their infinity support both
materially and time. Never the less my friend Kitowe Mariam for her inspiration to complete this
pamphlet. BSc.Age/Bpe for their intention I appreciate too .Mr Deus,Heri,David(Age) for their
materials as far as many supporters participated in the preparation of this pamphlet.
God bless you.
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5. Dedication
This pamphlet is dedicated to all Engineering students at Sokoine University of Agriculture
taking BPE211/AE213(Applied thermodynamic)-2017 and all upcoming youngs at this
institution.
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6. Table of content
About the author……………………………………………………………………..
Foreword……………………………………………………………………………..
Acknowledgement…………………………………………………………………...
Dedication……………………………………………………………………………
1. Fundamental concept of thermodynamics…………………………………..1
2. Thermodynamics properties of liquids,property diagrams…………………..
3. First law of Thermodynamics………………………………………………
4. Thermodynamics processes:Non flow and flow processes…………………..
5. Second law of thermodynamics……………………………………………...
6. Carnot cycle and Gas power system…………………………………………
7. Steam/Vapour power…………………………………………………………
8. Refrigeration cycles………………………………………………………….
9. Properties of mixtures……………………………………………………….
10. Psychometry…………………………………………………………………
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7. TOPIC 1
FUNDAMENTAL CONCEPT OF THERMODYNAMICS
Thermodynamic System
Thermodynamics is the science relating heat and work transfers and the related changes in the
properties of the working substance. The working substance is isolated from its surroundings in
order to determine its properties.
System - Collection of matter within prescribed and identifiable boundaries. A system may be
either an open one, or a closed one, referring to whether mass transfer or does not take place
across the boundary.
Types of Thermodynamic Systems
There are three mains types of system: open system, closed system and isolated system. All these
have been described below:
1) Open system: The system in which the transfer of mass as well as energy can take place
across its boundary is called as an open system. Our previous example of engine is an open
system. In this case we provide fuel to engine and it produces power which is given out, thus
there is exchange of mass as well as energy. The engine also emits heat which is exchanged with
the surroundings. The other example of open system is boiling water in an open vessel, where
transfer of heat as well as mass in the form of steam takes place between the vessel and
surrounding.
2) Closed system: The system in which the transfer of energy takes place across its boundary
with the surrounding, but no transfer of mass takes place is called as closed system. The closed
system is fixed mass system. The fluid like air or gas being compressed in the piston and
cylinder arrangement is an example of the closed system. In this case the mass of the gas remains
constant but it can get heated or cooled. Another example is the water being heated in the closed
vessel, where water will get heated but its mass will remain same.
3) Isolated system: The system in which neither the transfer of mass nor that of energy takes
place across its boundary with the surroundings is called as isolated system. For example if the
piston and cylinder arrangement in which the fluid like air or gas is being compressed or
expanded is insulated it becomes isolated system. Here there will neither transfer of mass nor
that of energy. Similarly hot water, coffee or tea kept in the thermos flask is closed system.
However, if we pour this fluid in a cup, it becomes an open system.
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8. Surroundings - Is usually restricted to those particles of matter external to the system which
may be affected by changes within the system, and the surroundings themselves may form
another system.
Boundary - A physical or imaginary surface, enveloping the system and separating it from the
surroundings.
THERMODYNAMIC PROPERTIES.
Property - is any quantity whose changes are defined only by the end states and by the process.
Examples of thermodynamic properties are the Pressure, Volume and Temperature of the
working fluid in the system above.
Thermodynamic properties are related to the energy of the system, i.e. temperature, pressure,
mass, volume.
Extensive properties depend on the size or extent of the system, e.g. volume, mass, total energy.
Intensive properties are independent of size, e.g. temperature, pressure, entropy, density,
specific volume.
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9. Thermodynamic Process
When the system undergoes change from one thermodynamic state to final state due change in
properties like temperature, pressure, volume etc, the system is said to have undergone
thermodynamic process. Various types of thermodynamic processes are: isothermal process,
adiabatic process, isochoric process, isobaric process and reversible process. These have been
described below:
1) Isothermal process: When the system undergoes change from one state to the other, but
its temperature remains constant, the system is said to have undergone isothermal
process. For instance, in our example of hot water in thermos flask, if we remove certain
quantity of water from the flask, but keep its temperature constant at 50 degree Celsius,
the process is said to be isothermal process.
Another example of isothermal process is latent heat of vaporization of water. When we
heat water to 100 degree Celsius, it will not start boiling instantly. It will keep on
absorbing heat at constant temperature; this heat is called latent heat of vaporization.
Only after absorbing this heat water at constant temperature, water will get converted into
steam.
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10. 2) Adiabatic process: The process, during which the heat content of the system or certain
quantity of the matter remains constant, is called as adiabatic process. Thus in adiabatic
process no transfer of heat between the system and its surroundings takes place. The wall
of the system which does not allows the flow of heat through it, is called as adiabatic
wall, while the wall which allows the flow of heat is called as diathermic wall.
3) Isochoric process: The process, during which the volume of the system remains
constant, is called as isochoric process. Heating of gas in a closed cylinder is an example
of isochoric process.
4) Isobaric process: The process during which the pressure of the system remains constant
is called as isobaric process. Example: Suppose there is a fuel in piston and cylinder
arrangement. When this fuel is burnt the pressure of the gases is generated inside the
engine and as more fuel burns more pressure is created. But if the gases are allowed to
expand by allowing the piston to move outside, the pressure of the system can be kept
constant.
The constant pressure and volume processes are very important. The Otto and diesel
cycle, which are used in the petrol and diesel engine respectively, have constant volume
and constant pressure processes. In practical situations ideal constant pressure and
constant pressure processes cannot be achieved.
5) Reversible process: In simple words the process which can be revered back completely
is called a reversible process. This means that the final properties of the system can be
perfectly reversed back to the original properties. The process can be perfectly reversible
only if the changes in the process are infinitesimally small. In practical situations it is not
possible to trace these extremely small changes in extremely small time, hence the
reversible process is also an ideal process. The changes which occur during reversible
process are in equilibrium with each other
6) Irreversible process A process that is not reversible—duh. There will be entropy
generation in an irreversible process. Factors that can cause a process to be irreversible
include friction, unrestrained expansion, mixing of two gases, heat transfer across a finite
temperature difference, electric resistance, inelastic deformation of solids, and chemical
reactions.
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11. APPLICATION AREA OF THERMODYNAMICS
Application Areas of Thermodynamics
Some examples include the electric or gas range, the heating and air-conditioning systems, the
refrigerator, the humidifier, the pressure cooker, the water heater, the shower, the iron, and even the
computer and the TV. On a larger scale, thermodynamics plays a major part in the design and analysis of
automotive engines, rockets, jet engines, and conventional or nuclear power plants, solar collectors, and
the design of vehicles from ordinary cars to airplanes.
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12. QUESTIONS FOR TOPIC 1
All questions from this chapter are based on explanation (in words) so when meet with any
question refer the notes above…….,
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