Thermodynamics Chapter 1 - Faculty Personal Homepage

cemeterymarylandΜηχανική

27 Οκτ 2013 (πριν από 3 χρόνια και 7 μήνες)

95 εμφανίσεις

WCB/McGraw
-
Hill

© The McGraw
-
Hill Companies, Inc.,1998

Thermo
dynamics

Çengel

Boles

Third Edition

Thermo
dynamics


WCB/McGraw
-
Hill

© The McGraw
-
Hill Companies, Inc.,1998

Thermo
dynamics

Çengel

Boles

Third Edition

1

CHAPTER

Basic

Concepts of

Thermodynamics

WCB/McGraw
-
Hill

© The McGraw
-
Hill Companies, Inc.,1998

Thermo
dynamics

Çengel

Boles

Third Edition

Applications of
Thermodynamics

1
-
1

Power plants

The human body

Air
-
conditioning

systems

Airplanes

Car radiators

Refrigeration systems

WCB/McGraw
-
Hill

© The McGraw
-
Hill Companies, Inc.,1998

Thermo
dynamics

Çengel

Boles

Third Edition

Crossing Closed
-
System Boundries

1
-
2

(Fig. 1
-
13)

Energy, not mass, crosses closed
-
system boundries

WCB/McGraw
-
Hill

© The McGraw
-
Hill Companies, Inc.,1998

Thermo
dynamics

Çengel

Boles

Third Edition

Closed System with Moving
Boundry

1
-
3

WCB/McGraw
-
Hill

© The McGraw
-
Hill Companies, Inc.,1998

Thermo
dynamics

Çengel

Boles

Third Edition

Crossing Control Volume
Boundaries

1
-
4

Mass and Energy Cross Control Volume Boundaries

WCB/McGraw
-
Hill

© The McGraw
-
Hill Companies, Inc.,1998

Thermo
dynamics

Çengel

Boles

Third Edition

System’s Internal Energy

(Fig. 1
-
19)

1
-
5

System’s Internal Energy = Sum of Microscopic Energies

WCB/McGraw
-
Hill

© The McGraw
-
Hill Companies, Inc.,1998

Thermo
dynamics

Çengel

Boles

Third Edition

Quasi
-
Equilibrium,

Work
-
Producing Devices

(Fig. 1
-
30)

1
-
6

Quasi
-
Equilibrium, Work
-
Producing Devices Deliver the Most Work

WCB/McGraw
-
Hill

© The McGraw
-
Hill Companies, Inc.,1998

Thermo
dynamics

Çengel

Boles

Third Edition

Compressed Process
P
-
V

Diagram

(Fig. 1
-
31)

1
-
7

WCB/McGraw
-
Hill

© The McGraw
-
Hill Companies, Inc.,1998

Thermo
dynamics

Çengel

Boles

Third Edition

Absolute, Gage, and Vacuum
Pressures

(Fig. 1
-
36)

1
-
8

WCB/McGraw
-
Hill

© The McGraw
-
Hill Companies, Inc.,1998

Thermo
dynamics

Çengel

Boles

Third Edition

The Basic Manometer

1
-
9

WCB/McGraw
-
Hill

© The McGraw
-
Hill Companies, Inc.,1998

Thermo
dynamics

Çengel

Boles

Third Edition

Temperature Scales
Comparison

(Fig. 1
-
48)

1
-
10

WCB/McGraw
-
Hill

© The McGraw
-
Hill Companies, Inc.,1998

Thermo
dynamics

Çengel

Boles

Third Edition

Many Ways to Supply the Same
Energy

(Fig. 1
-
52)

1
-
11

Ways to supply a room with energy equalling a 300
-
W electric resistance heater

WCB/McGraw
-
Hill

© The McGraw
-
Hill Companies, Inc.,1998

Thermo
dynamics

Çengel

Boles

Third Edition

Bomb Calorimeter Used to

Determine Energy Content of Food

(Fig. 1
-
53)

1
-
12

WCB/McGraw
-
Hill

© The McGraw
-
Hill Companies, Inc.,1998

Thermo
dynamics

Çengel

Boles

Third Edition

Chapter Summary


Thermodynamics

is the science that primarily
deals with energy.

1
-
13

WCB/McGraw
-
Hill

© The McGraw
-
Hill Companies, Inc.,1998

Thermo
dynamics

Çengel

Boles

Third Edition

Chapter Summary


The
first law of thermodynamics
is simply an
expression of the conservation of energy
principle, and it asserts that
energy

is a
thermodynamic property.


The
second law of thermodynamics
asserts
that energy has
quality

as well as
quantity
, and
actual processes occur in the direction of
decreasing quality of energy.

1
-
14

WCB/McGraw
-
Hill

© The McGraw
-
Hill Companies, Inc.,1998

Thermo
dynamics

Çengel

Boles

Third Edition

Chapter Summary


A system of fixed mass is called a
closed
system
, or
control mass
, and a system that
involves mass transfer across its boundaries
is called an
open system
, or
control volume
.

1
-
15

WCB/McGraw
-
Hill

© The McGraw
-
Hill Companies, Inc.,1998

Thermo
dynamics

Çengel

Boles

Third Edition

Chapter Summary


The mass
-
dependent properties of a system
are called
extensive properties
and the others,
intensive properties
.
Density

is mass per unit
volume, and
specific volume
is volume per unit
mass.

1
-
16

WCB/McGraw
-
Hill

© The McGraw
-
Hill Companies, Inc.,1998

Thermo
dynamics

Çengel

Boles

Third Edition

Chapter Summary


The sum of all forms of energy of a system is
called
total energy
, which is considered to
consist of internal, kinetic, and potential
energies.
Internal energy
represents the
molecular energy of a system and may exist in
sensible, latent, chemical, and nuclear forms.

1
-
17

WCB/McGraw
-
Hill

© The McGraw
-
Hill Companies, Inc.,1998

Thermo
dynamics

Çengel

Boles

Third Edition

Chapter Summary


A system is said to be in
thermodynamic
equilibrium
if it maintains thermal, mechanical,
phase, and chemical equilibrium.

1
-
18

WCB/McGraw
-
Hill

© The McGraw
-
Hill Companies, Inc.,1998

Thermo
dynamics

Çengel

Boles

Third Edition

Chapter Summary


Any change from one state to another is called
a
process
.


A process with identical end states is called a
cycle
.

1
-
19

WCB/McGraw
-
Hill

© The McGraw
-
Hill Companies, Inc.,1998

Thermo
dynamics

Çengel

Boles

Third Edition

Chapter Summary


During a
quasi
-
static

or
quasi
-
equilibrium
process, the system remains practically in
equilibrium at all times.

1
-
20

WCB/McGraw
-
Hill

© The McGraw
-
Hill Companies, Inc.,1998

Thermo
dynamics

Çengel

Boles

Third Edition

Chapter Summary


The state of a simple, compressible system is
completely specified by two independent,
intensive properties.

1
-
21

WCB/McGraw
-
Hill

© The McGraw
-
Hill Companies, Inc.,1998

Thermo
dynamics

Çengel

Boles

Third Edition

Chapter Summary


Force per unit area is called
pressure
, and its
unit is the
pascal
. The absolute, gage, and
vacuum pressures are related by

1
-
22

WCB/McGraw
-
Hill

© The McGraw
-
Hill Companies, Inc.,1998

Thermo
dynamics

Çengel

Boles

Third Edition

Chapter Summary


Small to moderate pressure differences are
measured by a manometer, and a differential
fluid column of height h corresponds to a
pressure difference of




where


is the⁦luid density⁡nd g⁩s theocal
gravitational acceleration.

1
-
23

WCB/McGraw
-
Hill

© The McGraw
-
Hill Companies, Inc.,1998

Thermo
dynamics

Çengel

Boles

Third Edition

Chapter Summary


The atmospheric pressure is measured by a
barometer and is determined from





where h is the height of the liquid column
above the free surface.

1
-
24

WCB/McGraw
-
Hill

© The McGraw
-
Hill Companies, Inc.,1998

Thermo
dynamics

Çengel

Boles

Third Edition

Chapter Summary


The zeroth law of thermodynamics states that
two bodies are in thermal equilibrium if both
have the same temperature reading even if
they are not in contact.

1
-
25

WCB/McGraw
-
Hill

© The McGraw
-
Hill Companies, Inc.,1998

Thermo
dynamics

Çengel

Boles

Third Edition

Chapter Summary


The temperature scales used in the SI and the
English system today are the Celsius scale
and the Fahrenheit scale, respectively.

1
-
26

WCB/McGraw
-
Hill

© The McGraw
-
Hill Companies, Inc.,1998

Thermo
dynamics

Çengel

Boles

Third Edition

Chapter Summary


The absolute temperature scale in the SI is the
Kelvin scale, which is related to the Celsius
scale by

1
-
27

WCB/McGraw
-
Hill

© The McGraw
-
Hill Companies, Inc.,1998

Thermo
dynamics

Çengel

Boles

Third Edition

Chapter Summary


In the English system, the absolute
temperature scale is the Rankine scale, which
is related to the Fahrenheit scale by

1
-
28

WCB/McGraw
-
Hill

© The McGraw
-
Hill Companies, Inc.,1998

Thermo
dynamics

Çengel

Boles

Third Edition

Chapter Summary


The magnitudes of each division of 1 K and

1
0
C are identical, and so are the magnitude of
each division of 1 R and 1
0
F. Therefore,




and

1
-
29

WCB/McGraw
-
Hill

© The McGraw
-
Hill Companies, Inc.,1998

Thermo
dynamics

Çengel

Boles

Third Edition

Chapter Summary


An important application area of
thermodynamics is the biological system.
Most diets are based on the simple energy
balance: the net energy gained by a person in
the form of fat is equal to the difference
between the energy intake from food and the
energy expended by exercise.

1
-
30