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ThermodynamicsAn Engineering Approach
Fourth Edition
Yunus A. Çengel
Michael A. Boles
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
CHAPTER
1
Basic Concepts of Thermodynamics
Instructor’s Visual AidsHeat Work and Energy. A First Course in Thermodynamics© 2002, F. A. Kulacki
Chapter 1 Module 1 Slide 3Energy, Heat and Work
Introduction to Macroscopic Thermodynamics
• Mechanical Engineering– Mechanics– Energy– Systems– Design
The over arching goal is design of products to meet societal needs.
• Mechanical Engineering– Mechanics– Energy– Systems– Design
The over arching goal is design of products to meet societal needs.
General overviewGeneral overview
• Thermodynamics– A part of the Energy
component of mechanical engineering.
– Governs all energy consuming and transforming devices and system.
• Thermodynamics– A part of the Energy
component of mechanical engineering.
– Governs all energy consuming and transforming devices and system.
Instructor’s Visual AidsHeat Work and Energy. A First Course in Thermodynamics© 2002, F. A. Kulacki
Chapter 1 Module 1 Slide 4Energy, Heat and Work
Introduction to Macroscopic Thermodynamics
The engineering frameworkThe engineering framework
THEORY
JUDGMENT(DESIGN)
DATA
FIGURE 1–5Some application areas of thermodynamics.
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
1-1
Diet
Air vents
FIGURE 1–7The definition of the force units.
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
1-2
1 lbm will have a gravitational force on it of 1 lbf on earth.
Check for dimensional homogeneity!
Instructor’s Visual AidsHeat Work and Energy. A First Course in Thermodynamics© 2002, F. A. Kulacki
Chapter 1 Module 1 Slide 7Energy, Heat and Work
Introduction to Macroscopic Thermodynamics
Beginning ideas and Beginning ideas and concepts...concepts...
Instructor’s Visual AidsHeat Work and Energy. A First Course in Thermodynamics© 2002, F. A. Kulacki
Chapter 1 Module 1 Slide 8Energy, Heat and Work
Introduction to Macroscopic Thermodynamics
Macroscopic vs. microscopic Macroscopic vs. microscopic viewpoints...viewpoints...
A collection of atoms within a container, each with a unique velocity.
Instructor’s Visual AidsHeat Work and Energy. A First Course in Thermodynamics© 2002, F. A. Kulacki
Chapter 1 Module 1 Slide 9Energy, Heat and Work
Introduction to Macroscopic Thermodynamics
Number of atoms = N
Energy of each atom =2
2
1Vme
Total Energy =
N
i
keVmN
eN1
1
2
2
Energy in a microscopic descriptionEnergy in a microscopic description
Instructor’s Visual AidsHeat Work and Energy. A First Course in Thermodynamics© 2002, F. A. Kulacki
Chapter 1 Module 1 Slide 10Energy, Heat and Work
Introduction to Macroscopic Thermodynamics
The energy in both casesis the same, E. In the macroscopic description,atomistic concepts aredisregarded.
How we describe the system chosen for studyrequires careful selection ofproperties that are basedon observable, measurablequantities.
The macroscopic descriptionThe macroscopic description
Instructor’s Visual AidsHeat Work and Energy. A First Course in Thermodynamics© 2002, F. A. Kulacki
Chapter 1 Module 1 Slide 11Energy, Heat and Work
Introduction to Macroscopic Thermodynamics
The macroscopic The macroscopic viewpoint...viewpoint...
Instructor’s Visual AidsHeat Work and Energy. A First Course in Thermodynamics© 2002, F. A. Kulacki
Chapter 1 Module 1 Slide 12Energy, Heat and Work
Introduction to Macroscopic Thermodynamics
State of a thermodynamic system.
Enumeration of all of itsproperties.
In macroscopic thermodynamics, In macroscopic thermodynamics, the properties of system are the properties of system are assigned to the system as a whole.assigned to the system as a whole.
Instructor’s Visual AidsHeat Work and Energy. A First Course in Thermodynamics© 2002, F. A. Kulacki
Chapter 1 Module 1 Slide 13Energy, Heat and Work
Introduction to Macroscopic Thermodynamics
Properties in macroscopic thermodynamicsProperties in macroscopic thermodynamics
m
lim0
Den
sity
,
Molecular and atomicMolecular and atomiceffects are importanteffects are important
Limit of the macroscopic Limit of the macroscopic model and assumptions.model and assumptions.
(m3)
Instructor’s Visual AidsHeat Work and Energy. A First Course in Thermodynamics© 2002, F. A. Kulacki
Chapter 1 Module 1 Slide 14Energy, Heat and Work
Introduction to Macroscopic Thermodynamics
How does the state of How does the state of system change?system change?
Instructor’s Visual AidsHeat Work and Energy. A First Course in Thermodynamics© 2002, F. A. Kulacki
Chapter 1 Module 1 Slide 15Energy, Heat and Work
Introduction to Macroscopic Thermodynamics
SystemSystem
Energetic interactionsEnergetic interactions
Surroundings
EnergyFlow
System BoundarySystem Boundary
Instructor’s Visual AidsHeat Work and Energy. A First Course in Thermodynamics© 2002, F. A. Kulacki
Chapter 1 Module 1 Slide 16Energy, Heat and Work
Introduction to Macroscopic Thermodynamics
Basic definitions...Basic definitions...
Instructor’s Visual AidsHeat Work and Energy. A First Course in Thermodynamics© 2002, F. A. Kulacki
Chapter 1 Module 1 Slide 17Energy, Heat and Work
Introduction to Macroscopic Thermodynamics
SystemSystem
0dtdm
Closed System
Open System
Mass Flow
Mass Flow
Instructor’s Visual AidsHeat Work and Energy. A First Course in Thermodynamics© 2002, F. A. Kulacki
Chapter 1 Module 1 Slide 18Energy, Heat and Work
Introduction to Macroscopic Thermodynamics
System and surroundingsSystem and surroundingsUniverse = Systems +Surroundings
Closed SystemClosed System
SurroundingsSurroundings
System Boundary
Instructor’s Visual AidsHeat Work and Energy. A First Course in Thermodynamics© 2002, F. A. Kulacki
Chapter 1 Module 1 Slide 19Energy, Heat and Work
Introduction to Macroscopic Thermodynamics
System and surroundingsSystem and surroundings
Open systems have mass flow across their boundaries.
Open System( Fixed space orvolume)
Surroundings Control Surface
Mass flow
Instructor’s Visual AidsHeat Work and Energy. A First Course in Thermodynamics© 2002, F. A. Kulacki
Chapter 1 Module 1 Slide 20Energy, Heat and Work
Introduction to Macroscopic Thermodynamics
Interactions between Interactions between system and surroundings...system and surroundings...
Instructor’s Visual AidsHeat Work and Energy. A First Course in Thermodynamics© 2002, F. A. Kulacki
Chapter 1 Module 1 Slide 21Energy, Heat and Work
Introduction to Macroscopic Thermodynamics
Closed systemClosed system
System
Surroundings
Work
Heat
Instructor’s Visual AidsHeat Work and Energy. A First Course in Thermodynamics© 2002, F. A. Kulacki
Chapter 1 Module 1 Slide 22Energy, Heat and Work
Introduction to Macroscopic Thermodynamics
Open systemOpen system
System
Surroundings
Mass Flow
Mass Flow
Power
Heat
Usually look at rates.
Instructor’s Visual AidsHeat Work and Energy. A First Course in Thermodynamics© 2002, F. A. Kulacki
Chapter 1 Module 1 Slide 23Energy, Heat and Work
Introduction to Macroscopic Thermodynamics
Example: Piston and cylinder - a closed system
m
Gas at pressure, p
Piston
Instructor’s Visual AidsHeat Work and Energy. A First Course in Thermodynamics© 2002, F. A. Kulacki
Chapter 1 Module 1 Slide 24Energy, Heat and Work
Introduction to Macroscopic Thermodynamics
Example: The gas turbine engine - an open system
Shaft Work Output
Combustor
Fuel Flow In
Air Flow In
Exhaust Gases Out
Compressor Work Out
FIGURE 1–17A control volume may involve fixed, moving, real, and imaginary boundaries.
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
1-5
A control volume is an open system
Instructor’s Visual AidsHeat Work and Energy. A First Course in Thermodynamics© 2002, F. A. Kulacki
Chapter 1 Module 1 Slide 26Energy, Heat and Work
Introduction to Macroscopic Thermodynamics
Key concepts and termsKey concepts and terms
Closed SystemOpen System
System BoundarySurroundings
Universe Thermodynamic Properties
Thermodynamic State
Instructor’s Visual AidsHeat Work and Energy. A First Course in Thermodynamics© 2002, F. A. Kulacki
Chapter 1 Module 1 Slide 27Energy, Heat and Work
Introduction to Macroscopic Thermodynamics
Equilibrium states and Equilibrium states and propertiesproperties
Instructor’s Visual AidsHeat Work and Energy. A First Course in Thermodynamics© 2002, F. A. Kulacki
Chapter 1 Module 1 Slide 28Energy, Heat and Work
Introduction to Macroscopic Thermodynamics
PropertiesProperties
Properties:•Temperature•Pressure•Volume•Internal energy•Entropy
Properties:•Temperature•Pressure•Volume•Internal energy•Entropy
SystemSystem
The system can be either open or The system can be either open or closed. The concept of a propertyclosed. The concept of a property
still applies.still applies.
Instructor’s Visual AidsHeat Work and Energy. A First Course in Thermodynamics© 2002, F. A. Kulacki
Chapter 1 Module 1 Slide 29Energy, Heat and Work
Introduction to Macroscopic Thermodynamics
Classes of propertiesClasses of properties• ExtensiveExtensive
– MASSMASS– VOLUMEVOLUME– ENERGYENERGY
ADDITIVEADDITIVE OVER OVER
THE SYSTEMTHE SYSTEM..
• ExtensiveExtensive– MASSMASS– VOLUMEVOLUME– ENERGYENERGY
ADDITIVEADDITIVE OVER OVER
THE SYSTEMTHE SYSTEM..
• IntensiveIntensive– TEMPERATURETEMPERATURE– PRESSUREPRESSURE– DENSITYDENSITY
NOTNOT ADDITIVEADDITIVE OVER OVER
THE SYSTEMTHE SYSTEM..
• IntensiveIntensive– TEMPERATURETEMPERATURE– PRESSUREPRESSURE– DENSITYDENSITY
NOTNOT ADDITIVEADDITIVE OVER OVER
THE SYSTEMTHE SYSTEM..
Specific Properties
Continuum approach is valid if system is large compared to distance between molecules
Instructor’s Visual AidsHeat Work and Energy. A First Course in Thermodynamics© 2002, F. A. Kulacki
Chapter 1 Module 1 Slide 30Energy, Heat and Work
Introduction to Macroscopic Thermodynamics
StateState
• At a given state, all the properties of the system have fixed values.
• If the value of one property changes, the state changes.
• If no properties are changing, then it is at equilibrium
Instructor’s Visual AidsHeat Work and Energy. A First Course in Thermodynamics© 2002, F. A. Kulacki
Chapter 1 Module 1 Slide 31Energy, Heat and Work
Introduction to Macroscopic Thermodynamics
EquilibriumEquilibrium
• Thermodynamics deals with equilibrium states.
• No driving forces
• Mechanical equilibrium– No change in pressure with time
• Thermal equilibrium– Temperature is same throughout system
Instructor’s Visual AidsHeat Work and Energy. A First Course in Thermodynamics© 2002, F. A. Kulacki
Chapter 1 Module 1 Slide 32Energy, Heat and Work
Introduction to Macroscopic Thermodynamics
EquilibriumEquilibrium
• Phase equilibrium– No change in the amounts of different phases
• Chemical equilibrium– Chemical composition does not change with
time.
Instructor’s Visual AidsHeat Work and Energy. A First Course in Thermodynamics© 2002, F. A. Kulacki
Chapter 1 Module 1 Slide 33Energy, Heat and Work
Introduction to Macroscopic Thermodynamics
State PostulateState Postulate
• The state of a simple compressible system is completely specified by two independent, intensive properties
• Simple compressible system:– Absence of electrical, magnetic, gravitational,
motion and surface tension effects.
– Independent if one property can be held constant while another is varied
