Chap 2. The second law of thermodynamics

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Chapter. 2

The second law of

thermodynamics

Chap 2. The second law of thermodynamics

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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