Chapter. 2 The second law of thermodynamics -...
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Chap 2. The second law of thermodynamics Thermal Engineering Lab., Dept. of Mechanical Engineering, Sogang University -1- Chapter. 2 The second law of thermodynamics
Transcript of Chapter. 2 The second law of thermodynamics -...
Chap 2. The second law of thermodynamics
Thermal Engineering Lab., Dept. of Mechanical Engineering, Sogang University -1-
Chapter. 2
The second law of
thermodynamics
Chap 2. The second law of thermodynamics
Thermal Engineering Lab., Dept. of Mechanical Engineering, Sogang University -2-
2.1 The second law for closed systems
Chap 2. The second law of thermodynamics
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2.1.1 Cycle in contact with one temperature reservoir
0
0
W
Q
Kelvin-Planck statement: It is impossible to construct an engine which will work in a complete cycle, and produce no effect except the raising of a weight and the cooling of a heat reservoir.
Chap 2. The second law of thermodynamics
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2.1.2 Cycle in contact with two temperature reservoirs
1 2
Assume 0
Q Q W
W
Chap 2. The second law of thermodynamics
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1 2
1 2
1 2
1 2
1. 0 & 0
Violation of 1st law
2. 0 & 0
Violation of 2nd law
3. 0
Assume
0 & 0
Q Q
Q Q
Q Q
Q Q
2 2
1 1
21 2
1
( , )
rev
rev
Q Q
Q Q
Qf T T
Q
Chap 2. The second law of thermodynamics
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1 2
1 2
+ 0 Q Q
T T
Chap 2. The second law of thermodynamics
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2.1.3 Cycle in contact with any number of temperature reservoirs
1 2
1 2
+ + 0
0
n
n
QQ Q
T T T
Q
T
Chap 2. The second law of thermodynamics
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2.2 The second law for open systems
0
igen
i in outi
gen
QdSms ms S
dt T
S
( ) 1gen
V A A
sdV q ndA sv ndA S
t T
gen
gen
s qv s s
t T
Ds qs
Dt T
Chap 2. The second law of thermodynamics
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2.3 Local thermodynamic equilibrium model
Local thermodynamic equilibrium: time scale of the process >> local relaxation time
Chap 2. The second law of thermodynamics
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2.4 The entropy maximum and energy minimum principles
Chap 2. The second law of thermodynamics
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Chap 2. The second law of thermodynamics
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2.5 Caratheodory’s two axioms
Chap 2. The second law of thermodynamics
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2.6 A heat transfer man’s two axioms
Chap 2. The second law of thermodynamics
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2.7 Historical background
