ThermoDynamics

KNUST PHY 255

A. Britwum (PhD) and H. Martin (AMIMA)

September 6, 2018

Henry Martin (AMIMA) KNUST PHY 255 September 6, 2018 1 / 24

Outline of Presentation

1 Definition & History

2 Objectives & Goals of Course
3 Areas of Application
4 Course Outline
5 Books Recommended
6 Assessment
7 How to appreciate ThermoD
8 Revision
9 Assignment for the Week &
Next Lecture Topics
.

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Definition & History
What is ThermoDynamics????
Nicolas Léonard Sadi Carnot (father of
thermodynamics). ’Reflections on the Motive
Power of Fire’ (1824): a discourse on heat,
power, and engine efficiency. A quest to
improve the efficiency of the first engine built
by Thomas Savery.
Lord Kelvin (William Thomson) ’Dynamical
Theory of Heat’ (1854): ”Thermo-dynamics is
the subject of the relation of heat to forces
acting between contiguous parts of bodies, and
the relation of heat to electrical agency”
Is the theory that deals with the flow of energy
(temperature, heat and work) in systems.

Henry Martin (AMIMA) KNUST PHY 255 September 6, 2018 3 / 24

Definition & History
What is ThermoDynamics????
Nicolas Léonard Sadi Carnot (father of
thermodynamics). ’Reflections on the Motive
Power of Fire’ (1824): a discourse on heat,
power, and engine efficiency. A quest to
improve the efficiency of the first engine built
by Thomas Savery.
Lord Kelvin (William Thomson) ’Dynamical
Theory of Heat’ (1854): ”Thermo-dynamics is
the subject of the relation of heat to forces
acting between contiguous parts of bodies, and
the relation of heat to electrical agency”
Is the theory that deals with the flow of energy
(temperature, heat and work) in systems.

Henry Martin (AMIMA) KNUST PHY 255 September 6, 2018 3 / 24

Definition & History
What is ThermoDynamics????
Nicolas Léonard Sadi Carnot (father of
thermodynamics). ’Reflections on the Motive
Power of Fire’ (1824): a discourse on heat,
power, and engine efficiency. A quest to
improve the efficiency of the first engine built
by Thomas Savery.
Lord Kelvin (William Thomson) ’Dynamical
Theory of Heat’ (1854): ”Thermo-dynamics is
the subject of the relation of heat to forces
acting between contiguous parts of bodies, and
the relation of heat to electrical agency”
Is the theory that deals with the flow of energy
(temperature, heat and work) in systems.

Henry Martin (AMIMA) KNUST PHY 255 September 6, 2018 3 / 24

Objectives & Goals of Course

To understand the underlying Principles of transfer of energy

(heat, work and their interplay) in system(s) and its
surroundings.
The involvement of various fields of application.

Henry Martin (AMIMA) KNUST PHY 255 September 6, 2018 4 / 24

Areas of Application

All life activities by design involve some interaction between

energy and matter.

Henry Martin (AMIMA) KNUST PHY 255 September 6, 2018 5 / 24

Course Outline I

1 Revision
Thermodynamics System (s)
Number of particles, Volume, Temperature & Pressure
Equation of state
2 Energy (heat, work, internal energy · · ·)
Heat (Specific heat at constant pressure and constant volume)
Generalised concept of work
Mechanical equivalent of heat (Conditions for thermal and
mechanical equilibria)
Internal energy
The first law as statement of conservation of energy
3 Entropy (State and Directionality)
Entropy as a function of state

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Course Outline II
The second law of thermodynamics (Clausius theorem, Kelvin
statement and Principle of caratheordory)
Entropy’s reversibility, equilibrium, Principle of increase and
unavailability
Entropy’s disorderliness, direction of time and its flow and
production.
Introduction to irreversible thermodynamics (Reversible and
irreversible processes)
Carnot’s theorem and corollary (Examples of Carnot’s cycle)
Clausius-Clapeyron equation
4 Potential and its derivatives
Helmholtz and Gibbs free energies; enthalpy.
Legendre transformations of the thermodynamic potentials.
Physical significance of the potentials.
The Maxwell relations.

Henry Martin (AMIMA) KNUST PHY 255 September 6, 2018 7 / 24

Course Outline III

5 Application (Condensed Matter Physics)

Gibbs free energy and phase transitions.
Order of phase transitions. Examples.
The Clausius-Clapeyron equation. Polymorphic transitions (Ice,
carbon, etc)
Methods of liquefaction of gases: Joule-Thompson cooling;
Adiabatic demagnetization of paramagnetic states.
Measurement of low temperatures.
Introduction to superfluidity and superconductivity

Henry Martin (AMIMA) KNUST PHY 255 September 6, 2018 8 / 24

Books Recommended

1 History of Thermodynamics: The Doctrine of Energy and

Entropy, Ingo Müller, Springer-Verlag Berlin Heidelberg (2007)
2 An introduction to Thermal Physics, Daniel V. Schroeder,
Addison Wesley Longman (2000)
3 Thermodynamics: An engineering approach, Yunus A. and
Michael A. Boles, 5th ed.

Henry Martin (AMIMA) KNUST PHY 255 September 6, 2018 9 / 24

Assessment

1 Assignments: After every lecture

Submission format: Hand written before tutorial class
2 Mid-Sem:
3 Project: Groups of four (4) would randomly choose a project
based on thermodynamics & computing.
Submission format: Typed and presentation after mid-sem
holidays.
4 Exams: Multiple choice question (min: 50)

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How to appreciate ThermoD

Ingo Müller
1 Conventional style: words and subjective thinking

2 Scientific style: mathematical reasoning & formulation

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Number of particles, Volume, Temperature &
Pressure

Number of particle(N) is the quantity/amount of constituent in a

system.
N = nNA (1)
Volume is a 3D occupancy of the system.

Temperature is the measure of a systems’s hotness or coldness. This

also admired atomistically, as the average kinetic energy of random
motion of particles within a system.
Measured with a thermometer, calibrated in different
temperature scales ( Celsius scale (centigrade) ◦ C, Fahrenheit
scale ◦ F, and Kelvin scale K).

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 Conversion ◦ F →◦ C
◦ 5
C = (◦ F − 32) (2)
9
Kelvin scale (K), Absolute temperature: is independent of the
properties of particular materials and the constituent particles
has no classical motion
◦
C = K − 273.16 (3)

These scales differ in

1 the choice of zero unit/degree mark
2 the magnitudes of incremental units/degrees
Pressure (P) is the force applied to the surface of a system.
Measured in Pascal (Pa), atmosphere (atm).

1atm = 101325Pa (4)

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Thermodynamics System & it’s Surroundings

What is Thermodynamics System????

Nicolas Léonard Sadi Carnot described it as
a ”working substance”
Rudolf Clausius ’On the Motive Power of
Fire’ (1850), with the introduction of
surrounding describing it as a ”working
body”.

A thermodynamic system is the space/domain of constituent

particle(s) of matter for the flow of energy.
The surrounding space interacting with the system is called
environment.

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The transfer/passage of matter or energy from the system to the
environment and vice versa is through the boundary. Resulting in a
type of system as:
An isolated system cannot exchange energy or matter with the
environment.
A closed system can exchange energy with the environment but
not matter.
An open system can exchange both energy and matter with the
environment.

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The dis-allowance or allowance of flow/transfer of energy or matter
between the system and it’s surroundings constituting the above
types of systems is due to a specific type of boundary/wall. This
boundary/wall can be
Adiabatic - Does not allow heat to flow in/out.
Diathermal - Allows heat to flow in/out but not matter.
Permeable - Allows transfer of matter
Semi-permeable - Allow some certain kinds of matter

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Physical properties of the thermodynamics systems are classified as:
intensive property (inEXtensive): the systems property is
independent of its size/mass. Eg: T, P, c, cp , ρ and others.
extensive property (EXtent): the systems property depends on
the systems size/mass. Eg: n, V, E, S, H and others.
Based on these properties, systems can be classified as
Homogeneous: if every intensive property has the same value for
every point of the system (subsystem).

Z = mz (5)

Heterogeneous: if the intensive property of one portion is

different from the property of another portion.
X
Z= mi zi (6)
i

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State variables and Equation of state

Thermodynamic state variables are the properties of a

thermodynamic system in a specific state(form) of matter.
The relationship/characteristics between any two properties is clearer
by a state function, which is represented in an equation of state. Eg.
y = f (x), In thermoD, P = f (V )
Two or more state variables could also be relate to another in a
functional form. thus, f (T , S)
A passage from one thermodynamic state to another (Path) in a
thermodynamic system is known as a thermodynamic process.

Henry Martin (AMIMA) KNUST PHY 255 September 6, 2018 18 / 24

Next Lecture Topics

Energy (heat, work, internal energy · · ·)

Heat (Specific heat at constant pressure and constant volume)
Generalised concept of work
Mechanical equivalent of heat (Conditions for thermal and
mechanical equilibria)
Internal energy
The first law as statement of conservation of energy

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Assignment 1 I
1 If you placed a can of coke-cola into the refrigerator to cool.
Would you model the can of coke-cola as a closed system or as
an open system? Explain.
2 How do you relate heat, internal energy and thermal energy to
each other?
3 What is mechanical energy? How does it differ from thermal
energy? What are the forms of mechanical energy of a fluid
stream?
4 An aluminum pan whose thermal conductivity is 237 W/m ·◦ C
has a flat bottom whose diameter is 20 cm and thickness 0.4
cm. Heat is transferred steadily to boiling water in the pan
through its bottom at a rate of 500 W. If the inner surface of
the bottom of the pan is 105 ◦ C, determine the temperature of
the outer surface of the bottom of the pan.
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Assignment 1 II

5 Assuming, a standing man can be modelled as a 30cm diameter,

170cm long vertical cylinder with both the top and bottom
surfaces insulated and with the side surface at an average
temperature of 34 ◦ C. For a convection heat transfer coefficient
of 15 W/m2 ·◦ C, determine the rate of heat loss from this man
by convection in an environment at 20 ◦ C.
6 A mass of 2.4 kg of air at 150 kPa and 12 ◦ C is contained in a
gas-tight, frictionless piston cylinder device. The air is now
compressed to a final pressure of 600 kPa. During the process,
heat is transferred from the air such that the temperature inside
the cylinder remains constant. Calculate the work input during
this process

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Assignment 1 III
7 Consider a 1000 W iron whose base plate is made of 0.5 cm
thick aluminium alloy 2024-T6 (ρ = 2770 kg/m3 and cp = 875
J/kg ·◦ C). The base plate has a surface area of 0.03m2 . Initially,
the iron is in thermal equilibrium with the ambient air at 22 ◦ C.
Assuming 85 percent of the heat generated in the resistance
wires is transferred to the plate, determine the minimum time
needed for the plate temperature to reach 140 ◦ C.
8 For a cycle, is the net work necessarily zero? For what kind of
systems will this be the case?
9 On a hot day, a student turns his fan on when he/she was
leaving the room in the morning. Will the room be warmer or
cooler than the neighbouring rooms, When he/she returns in the
evening? Why? Assume all the doors and windows are kept
closed.

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Henry Martin (AMIMA) KNUST PHY 255 September 6, 2018 23 / 24
 THANK YOU

Henry Martin (AMIMA) KNUST PHY 255 September 6, 2018 24 / 24