Tehnička termodinamika - Kemijsko-tehnološki fakultet

_____________________________________________Prvi glavni zakon termodinamike
b)
Q 1 ,2 = 0
w
T
2
⎛ p
= T1
⎜
⎝ p
2
1
⎞
⎟
⎠
κ −1
κ
⎛ 1 ⎞
= 298⎜
⎟
⎝ 4 ⎠
1.4 −1
logT
2 = log 298 + log
1.4
R
= 1 T
κ −1
T 2 = 200 K
8.314
29
1.4 −1
1.4−1
1.4
1
4
( T − ) = ( 298 200)
1,2
2
−
−1
w1,2
= 70.24 kJ kg
c)
w
T
2
⎛ p
= T1
⎜
⎝ p
2
1
⎞
⎟
⎠
= R
1
n −1
T
n−1
n
T 2 = 237 K
⎛ 1 ⎞
= 298⎜
⎟
⎝ 4 ⎠
8.314
29
1.2 −1
1.2−1
1.2
( T − ) = ( 298 237)
1,2
2
−
−1
w1,2
= 87.44 kJ kg
n − κ 20.93 1.2 −1.4
q1,2
= cv
2 T1
−
n −1
29 1.2 −1
( T − ) = ⋅ ( 237 298)
−1
q1,2
= 44.03 kJ kg
91