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4132
A cylinder is initially filled with saturated liquidvapor mixture of R134a at a specified pressure.
Heat is transferred to the cylinder until the refrigerant vaporizes completely at constant pressure. The
initial volume, the work done, and the total heat transfer are to be determined, and the process is to be
shown on a
P
v
diagram.
Assumptions
1
The cylinder is stationary and thus the kinetic and potential energy changes are
negligible.
2
The thermal energy stored in the cylinder itself is negligible.
3
The compression or
expansion process is quasiequilibrium.
Analysis
(
a
) Using property data from R134a tables (Tables A11 through A13), the initial volume
of the refrigerant is determined to be
()
3
m
0.006098
=
=
=
=
×
+
=
+
=
=
−
×
+
=
+
=
=
=
=
=
⎭
⎬
⎫
=
=
/kg
m
0.03049
kg
0.2
kJ/kg
143
.
94
21
.
186
0.3
38.28
/kg
m
0.03049
0.0007533)
(0.099867
0.3
0.0007533
kJ/kg
.21
186
,
28
.
38
/kg
m
0.099867
,
0007533
.
0
3
.
0
kPa
200
3
1
1
1
1
3
1
1
3
1
1
V
m
u
x
u
u
x
u
u
x
P
fg
f
fg
f
fg
f
g
f
(
b
) The work done during this constant pressure process is
kJ/kg
224.48
/kg
m
0.09987
vapor
sat.
kPa
200
kPa
200
@
2
3
kPa
200
@
2
2
=
=
=
=
⎭
⎬
⎫
=
g
g
u
u
v
v
P
(
)
(
)
kJ
2.78
=
⎟
⎟
⎠
⎞
⎜
⎜
⎝
⎛
⋅
−
=
−
=
−
=
=
∫
3
3
1
2
1
2
2
1
out
,
m
kPa
1
kJ
1
/kg
m
0.03049
0.09987
kPa
200
kg
0.2
)
(
mP
P
d
P
W
b
(
c
) We take the contents of the cylinder as the system. This is a closed system since no mass enters or
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 Spring '06
 OLER

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