Suez University
Faculty of Petroleum
and Mining Engineering
Course Title: Thermodynamics
BSE 224
Sem. 2 – 2022-2023
Lecture No. 1: Course introduction
Dr. Salwa Mansour
1
Welcoming
&
Course Description
Course Description
Concepts and definitions - Properties of pure substances Different forms of energy - Concepts of Heat and work - first
law of thermodynamics - Applications of first law on closed
system and control volume - Second law of thermodynamics –
Entropy and isentropic efficiency.
3
Lectures Layout
Week
Topics
1
• Lecture1: Course introduction and lectures layout
2
• Lecture 2: Basic Concepts of Thermodynamics
3
• Lecture 3: Properties of Pure Substance
4
• Lecture 4: The Ideal-gas Equation of State + Quiz (1)
5
• Lecture 5: Energy and Energy Transfer
6
• Lecture 6: The First Law of Thermodynamics
4
Lectures Layout
Week
Topics
7
• Lecture 7: Application of First Law of Thermodynamics
+ Quiz (2)
8
• Midterm Exam
9
• Lecture 8: The Second Law of Thermodynamics
10
• Lecture 9: Entropy
11
• Lecture 10: Isentropic Efficiencies of Steady-Flow
Devices + Quiz (3)
5
Lectures Layout
Week
Topics
12
• Lecture 11: Gas Power Cycles
13
• Lecture 12: Vapor Power Cycles
14
• Course Review
References
1. Yunus A. Çengel, Michael A. Boles- Thermodynamics_ An Engineering Approach McGraw-Hill Education (2019).
2. Holman, J. P., Thermodynamics, McGraw-Hill, New York. Streeter, Victor, L., Fluid
Mechanics, 5th Edition, McGraw-Hill, New York, ISBN
6
Grading Policy
No.
Assessment Method
Degree
1
Quizzes
10
2
Reports
10
3
Oral Exam
20
4
Mid Term
20
5
Final Exam
90
Total
150
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Introduction To Thermodynamics
• Thermodynamics: The science of energy.
• Energy: The ability to cause changes.
• The name thermodynamics stems from the Greek words thermo
(heat) and dynamic (power).
• Conservation of energy principle: During an interaction,
energy can change from one form to another but the total
amount of energy remains constant.
• Energy cannot be created or destroyed.
• The first law of thermodynamics: An expression
of the conservation of energy principle.
• The first law asserts that energy is a thermodynamic property.
Energy cannot be created or
destroyed; it can only change forms
(the first law).
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Introduction To Thermodynamics
• The second law of thermodynamics: It asserts
that energy has quality as well as quantity, and
actual
processes occur in the direction of
decreasing quality of energy.
• Classical thermodynamics: A macroscopic
approach to the study of thermodynamics that
does not require a knowledge of the behavior of
individual particles.
• It provides a direct and easy way to the solution of
engineering problems and it is used in this course.
• Statistical thermodynamics: A microscopic
approach, based on the average behavior of large
groups of individual particles.
9
Application Areas of Thermodynamics
• All activities in
nature involve
some interaction
between energy
and matter; thus,
it is hard to
imagine an area
that does not
relate to
thermodynamics
in some manner.
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Importance Of Dimensions And Units
• Any physical quantity can be characterized by
dimensions.
• The magnitudes assigned to the dimensions are
called units.
• Some basic dimensions such as mass m, length L,
time t, and temperature T are selected as primary
or fundamental dimensions, while others such as
velocity V, energy E, and volume V are expressed
in terms of the primary dimensions and are called
secondary dimensions, or derived dimensions.
• Metric SI system: A simple and logical system
based on a decimal relationship between the
various units.
• English system: It has no apparent systematic
numerical base, and various units in this system
are related to each other rather arbitrarily.
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Importance Of Dimensions And Units
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Systems And Control Volumes
• System: A quantity of matter or a region in space chosen
for study.
• Surroundings: The mass or region outside the system
• Boundary: The real or imaginary surface that separates
the system from its surroundings.
• The boundary of a system can be fixed or movable.
• Systems may be considered to be closed or open.
• Closed system (Control mass): A fixed amount of mass,
and no mass can cross its boundary.
“Mass cannot cross the boundaries of a closed system, but energy can.”
• Isolated System: A special type of closed system that
does not interact in any way with its surroundings
“Neither mass or energy can cross the boundaries of a system”
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Systems And Control Volumes
• Open system (control volume): A properly
selected region in space.
• It usually encloses a device that involves mass
flow
such as a compressor, turbine, or nozzle.
• Both mass and energy can cross the boundary
of a control volume.
• Control surface: The boundaries of a
control volume. It can be real or
imaginary.
• A control volume can involve fixed, moving,
real, and imaginary boundaries.
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Systems And Control Volumes
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Systems And Control Volumes
• Working Fluid or Working Medium: the substance within
the boundary of a system that under goes changes and this
affecting the behaviour of the system.
• The properties of the System: are macroscopic
characteristics for defining the state of a system such as mass,
volume, energy, pressure, and temperature.
• Properties are considered to be either intensive or extensive.
• Intensive properties: Those that are independent of the mass
of a system, such as temperature, pressure, and density.
• Extensive properties: Those whose values depend on the
size—or
extent—of the system.
• Specific properties: Extensive properties per unit mass.
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State And Equilibrium
• State of the system: refers to the condition
of a system as described by its properties.
• Thermodynamics deals with equilibrium
states.
• Equilibrium: A state of balance.
• In an equilibrium state there are no
unbalanced potentials (or driving forces)
within the system.
• Thermal equilibrium: If the temperature
is the same throughout the entire system.
• Mechanical equilibrium: If there is no change
in pressure at any point of the system with time.
• Phase equilibrium: If a system involves two phases and when the mass of each phase
reaches an equilibrium level and stays there.
• Chemical equilibrium: If the chemical composition of a system does not change with time,
that is, no chemical reactions occur.
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Processes And Cycles
• Process: Any change that a system
undergoes from
one equilibrium state to another.
• Path: The series of states through which a
system passes during a process.
• To describe a process completely, one
should specify the initial and final states,
as well as the path it follows, and the
interactions with the surroundings.
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Processes And Cycles
• There
are
different
types
the
thermodynamic Process of any closed
system;
• Isothermal process: A process during
which the
temperature T remains constant.
• Isobaricprocess:A process during which
the pressure P remains constant.
• Isochoric (or isometric) process: A process
during which the specific volume v
remains constant.
• Cycle: A process during which the initial
and final
states are identical.
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The Steady-Flow Process
• The term steady implies no change with time. The opposite of
steady is
unsteady, or transient.
• A large number of engineering devices operate for long periods
of time under the same conditions, and they are classified as
steady-flow devices.
• Steady-flow process: A process during which a fluid flows
through a control volume steadily.
• Steady-flow conditions can be closely approximated by devices
that are intended for continuous operation such as turbines,
pumps, boilers, condensers, and heat exchangers or power
plants or refrigeration systems.22
20
Temperature And The Zeroth Law Of Thermodynamics
• The zero law of thermodynamics: If two bodies are in
thermal equilibrium with a third body, they are also in
thermal equilibrium with each other.
• By replacing the third body with a thermometer, the
zero law can be restated as two bodies are in thermal
equilibrium if both have the same temperature reading
even if they are not in contact.
21
Temperature And The Zeroth Law Of Thermodynamics
• Ice point: A mixture of ice and water that is in
equilibrium with air saturated with vapor at 1 atm
pressure (0°C or 32°F).
• Steam point: A mixture of liquid water and water
vapor (with no air) in equilibrium at 1 atm
pressure (100°C or 212°F).
• Celsius scale: in SI unit system
• Fahrenheit scale: in English unit system
• Thermodynamic temperature scale: A temperature
scale that is independent of the properties of any
substance.
• Kelvin scale (SI) Rankine scale (E)
22
Temperature And The Zero Law Of Thermodynamics
Comparison of temperature scales.
23
Pressure
• Pressure: A normal force exerted by a fluid per unit area
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Pressure
• Absolute pressure: The actual pressure at a given position. It is measured relative to absolute vacuum (i.e.,
absolute zero pressure).
• Gage pressure: The difference between the absolute pressure and the local atmospheric pressure. Most
pressure-measuring devices are calibrated to read zero in the atmosphere, and so they indicate gage pressure.
• Vacuum pressures: Pressures below atmospheric pressure.
Throughout this course, the pressure P
will denote absolute pressure unless
specified otherwise.
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Pressure
• Pascal’s law: the pressure applied to a confined fluid increases the pressure
throughout by the same amount.
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Pressure
• Barometer: a device used to measure
the atmospheric pressure
• Manometer: a device commonly used
to measure small and moderate pressure
differences
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Examples
Example 1: A manometer is used to measure the pressure of a gas in a tank. The
fluid used has a specific gravity of 0.85, and the manometer column height is 55
cm, as shown in Fig. 1-56. If the local atmospheric pressure is 96 kPa, determine
the absolute pressure within the tank.
Solution
28
Examples
Example 2: The basic barometer can be used to measure the height of a building.
If the barometric readings at the top and at the bottom of a building are 675 and
695 mmHg, respectively, determine the height of the building. Take the densities of
air and mercury to be 1.18 kg/m3 and 13,600 kg/m3, respectively.
Solution
29
Examples
30
Examples
Example 3: A gas is contained in a vertical, frictionless piston-cylinder
device. The piston has a mass of 3.2 kg and a cross-sectional area of 35
cm2. A compressed spring above the piston exerts a force of 150 N on the
piston. If the atmospheric pressure is 95 kPa, determine the pressure inside
the cylinder.
Solution
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☺Homework
1. Explain why some people experience nose bleeding and some others
experience shortness of breath at high elevations.
2. A vertical piston–cylinder device contains a gas at a
pressure of 100 kPa. The piston has a mass of 10 kg
and a diameter of 14 cm. Pressure of the gas is to be
increased by placing some weights on the piston.
Determine the local atmospheric pressure and the mass
of the weights that will double the pressure of the gas
inside the cylinder.
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Any Questions ?
Thank You