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CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER 11111111
THERMODYNAMICS
SMJ 2403/SME 1413
INSTRUCTOR: DR. MAZLAN ABDUL WAHID
TEXT: Thermodynamics: An Engineering Approach
( 5/edition ) by Yunus A. Çengel & Michael A. Boles
FACULTY OF MECHANICAL ENGINEERINGUNIVERSITI TEKNOLOGI MALAYSIASKUDAI, JOHOR, MALAYSIA
THERMODYNAMICSBASIC CONCEPTSBASIC CONCEPTSBASIC CONCEPTSBASIC CONCEPTSBASIC CONCEPTSBASIC CONCEPTSBASIC CONCEPTSBASIC CONCEPTS
MAZLAN
Yunus A. Çengel & Michael A. Boles
CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER 11111111Chapter 1Basic Concepts of Thermodynamics
•What is thermodynamics•Applications•Applications•Macroscopic view and microscopic view•Dimensions•Systems: Closed and open system•Properties of a system•State and equilibrium•Process and cycles
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•Process and cycles•Forms of energy•Temperature•Pressure
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CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER 11111111What is thermodynamics ?
Thermodynamics Defined as the science of energy
Greek words:
therme heat
dynamis
power
Greek words:
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power
Today: A subject talking about energy, energy transformation (on home appliances, power generation systems, transportation, etc) and relationship among properties of matter
CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER 11111111Some application areas of thermodynamics
FACULTY OF MECHANICAL ENGINEERINGUNIVERSITI TEKNOLOGI MALAYSIASKUDAI, JOHOR, MALAYSIA
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CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER 11111111More examples of thermodynamic applications
FACULTY OF MECHANICAL ENGINEERINGUNIVERSITI TEKNOLOGI MALAYSIASKUDAI, JOHOR, MALAYSIA
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CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER 11111111Thermodynamic approachMacroscopic and Microscopic view
Looking the system at its molecular level
Observing the system by taking the gross or average effects of many molecules
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MAZLAN
In this course we will deal only on the macroscopic view of thermodynamicsClassic Thermodynamics
at its molecular level (Kinetic theory)
average effects of many moleculesClassical Thermodynamics
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CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER 11111111Dimensions and Units
Primary dimensions
Derived or secondary dimensions
Name Length Time Mass Force
Int’l System (SI) Meter Sec Kilogram Newton
(m) (s) (kg) (kg. m/s2)
US (English - Engineering) Foot Sec Pound Mass
Pound Force
(ft) (s) lbm (lbf)
Force, F= ma=(kg)(m/s2)=N, Newton Weight, W=mg with g=9.81 m/s2
FACULTY OF MECHANICAL ENGINEERINGUNIVERSITI TEKNOLOGI MALAYSIASKUDAI, JOHOR, MALAYSIA
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Force, F= ma=(kg)(m/s2)=N, Newton Weight, W=mg with g=9.81 m/s2
In this course SI unit will be used most often
Velocity, V = length/time=(m)/(s)=m/s Work, W=Force*distance=(N)(m)1 Nm = 1 Joule
CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER 11111111Prefixes in SI
Multiple Prefix
1012
109
106
tera, Tgiga, Gmega, M106
103
102
101
10-1
10-2
10-3
mega, Mkilo, khecto, hdeka, dadeci, dcenti, cmilli, m
FACULTY OF MECHANICAL ENGINEERINGUNIVERSITI TEKNOLOGI MALAYSIASKUDAI, JOHOR, MALAYSIA
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10-3
10-6
10-9
10-12
milli, mmicro, µnano, npico, p
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CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER 11111111System, surroundings, and boundary
SURROUNDINGS
The region outside the system
A device or combination of devices containing a quantity of matter
SYSTEM
BOUNDARY
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The real or imaginary surfacethat separates the system from its surroundings.
CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER 11111111Closed and Open Systems
Closed systemor control mass
Mass = fixedEnergy = can flow in and out
Open systemor control volume
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or control volume
Mass = can flow in and outEnergy = can flow in and out
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CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER 11111111Properties of a system
Property – any characteristic of a systeme.g. pressure, p
temperature, Tvolume, V
• Specific Volume ( v = 1/ ρρρρ ) – volume per unit mass of a substance.
• Density ( ρρρρ = m/V) ) ) ) – mass per unit volume of a substance.
mass, m
Intensive properties– independent of size (p, T, ρ)ρ)ρ)ρ)
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Extensive properties– depend on size or extent of the system (m, V, E – total energy)
CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER 11111111
Pressure– the normal force exerted by a fluid on its containment vessel. For a fluid at rest, the pressure is the same in all directions.
δA
δFP n
δA'δA→→→→==== lim
area smallest the ===='δA
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continuum a considered be can that
area smallest the ===='δA
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CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER 11111111Gage pressure– the pressure measured relative to atmospheric pressure.
Atmospheric pressurePgag
Vacuum pressurethe pressure measured relative to atmospheric pressure P
Pvac
Pgage
Patm
Pabs = Patm +Pgage
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pressurePabs = Patm – Pvac
Patm m
CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER 11111111Atmospheric pressure - Barometer
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Patm = ρρρρgh
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CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER 11111111The Manometer Patm
P2 = Patm + ρρρρgh
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P1 = P2
density of fluid h
CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER 11111111
Pressure Measurement – Manometers
gHPPPgHP
APgAHAPAPmgAP
FF
B
B
B
BB updown
ρρρρ====−−−−====ρρρρ++++
====ρρρρ++++====++++
====
0
0
0downBF
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gHPgHPPB
ρρρρ====∆∆∆∆ρρρρ====−−−− 0
upBF
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CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER 11111111
P2 = Patm
P = P
AB
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PA = PBPA = PB
P1 + ρρρρgh1 + ρρρρgh2 = ρρρρgh3 + P2
CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER 11111111
A piston/cylinder with cross sectional area of 0.01 m2 has a piston mass of 100 kg resting on the stops, as shown in the figure. With an outside atmospheric pressure of 100 kPa, what should the water pressure be to lift the piston?
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CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER 11111111
Two cylinders are filled with liquid water, ρρρρ = 1000 kg/m3, and connected by a line with a closed valve. A has 100 kg and B has 500 kg of water, their cross-sectional areas are AA = 0.1 m2 and AB = 0.25 m2 and the height h is 1 m. Find the pressure on each side of the valve. The valve is opened and water m. Find the pressure on each side of the valve. The valve is opened and water flows to an equilibrium. Find the final pressure at the valve location.
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CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER 11111111
Two bodies have an equality of temperature if when they are in thermal contact with each other, we can observe no are in thermal contact with each other, we can observe no changes in their observable properties.
When two bodies have equality of temperature with a third
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When two bodies have equality of temperature with a third body, then they have equality of temperature each other.
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CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER 11111111
• Temperature Based on the Thermodynamic Behavior of a Substance– freezing and boiling point of water.
Boiling Pt.
• Absolute Temperature Scale–temperature scale independent of the thermodynamic properties of a particular substance.
Freezing Pt.
1527300 .++++==== CK
FACULTY OF MECHANICAL ENGINEERINGUNIVERSITI TEKNOLOGI MALAYSIASKUDAI, JOHOR, MALAYSIA
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Absolute Zero67459
1527300 .
.++++====++++====
FR
CK
CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER 11111111
Energy
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CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER 11111111
• MECHANICAL POTENTIAL ENERGY: Exists because of relative positions of two or more objects
MECHANICAL ENERGY
because of relative positions of two or more objects• MECHANICAL KINETIC ENERGY: Exists because
of relative velocities to two or more objects -- energy of motion
• MECHANICAL WORK: Mechanical energy in transition
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transition• When an object has been moved through a distance
against a resisting force (by, of course, an assisting force), mechanical work has been done.
CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER 11111111
• Intermolecular Potential Energy – energy associated with the force between associated with the force between molecules.
• Molecular Kinetic Energy – energy associated with the translational velocity of individual molecules.
• Intramolecular Energy – energy associated with the molecular and atomic structure.
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structure.
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CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER 11111111Forms of energy
Energy – found in many forms: thermal, mechanical, kinetic, potential, electric, magnetic, chemical, nuclear
Total Energy = Energythermal+ Energymechanical
+ Energykinetic
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CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER 11111111
• Phase– a quantity of matter that is homogeneous throughout the system or part of the system (gas, liquid, solid).
• States– condition of matter as defined by specific properties i.e.. temperature, pressure, etc.
• Properties– quantities that define the state of matter i.e.. temperature, pressure, etc.
• Intensive Properties– properties that are independent of mass.
• Extensive Properties– properties that vary with the mass being
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• Extensive Properties– properties that vary with the mass being considered.
• Thermodynamic Equilibrium – when all properties of the system are in equilibrium, i.e. not changing with time.
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CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER 11111111
• Process– a path of successive state through which a system passes.system passes.
• Equilibrium Process – process in which the successive states of the system can be described by the thermodynamic properties of the system.
• Quasi-equilibrium Process– process in which the deviation from thermodynamic equilibrium is infinitesimal.
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• Thermodynamic Cycle – when a system starts at an initial state and undergoes a sequence of changing states and then returns to its initial state.
CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER 11111111
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CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER CHAPTER 11111111
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