ENGR 2213 Thermodynamics

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ENGR 2213 Thermodynamics

• F. C. Lai
• School of Aerospace and Mechanical
• Engineering
• University of Oklahoma

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Enthalpy
H U pV
h u pv
dh du p dv v dp
du q - w
q du w
du p dv
dh v dp
For an ideal gas undergoes a constant
pressure process,
cp specific heat at constant pressure
cp cp (T)
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Enthalpy
h u pv
u RT
cp cv R
k cp / cv specific heat ratio
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Enthalpy
For compressed liquids,
v vf
u uf
h u pv
uf pvf
uf psatvf pvf psatvf
hf vf (p psat)
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Polytropic Process of an Ideal Gas
pVn constant
n ? 1
n 1
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Polytropic Process of an Ideal Gas
pVn constant
(pV)Vn-1 constant
(mRT)Vn-1 constant
TVn-1 constant
T1V1n-1 T2V2n-1 constant
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Polytropic Process of an Ideal Gas
pVn constant
(pV)np1-n constant
(mRT)np1-n constant
Tnp1-n constant
T1np11-n T2np21-n constant