This preview shows pages 1–3. Sign up to view the full content.
Solution of Homework 3
328
Complete the following table for Refrigerant134a
:
T,
°
C
P,
kPa
v
,
m
3
/ kg
Phase description
8
320
0.0007569
Compressed liquid
30
770.64
0.015
Saturated mixture
12.73
180
0.11041
Saturated vapor
80
600
0.044710
Superheated vapor
341
A rigid container that is filled with R134a is heated. The temperature and total enthalpy are
to be determined at the initial and final states.
Analysis
This is a constant volume process. The specific volume is
/kg
m
0014
.
0
kg
10
m
014
.
0
3
3
2
1
=
=
=
=
m
V
v
v
The initial state is determined to be a mixture, and thus the
temperature is the saturation temperature at the given
pressure. From Table A12 by interpolation
C
0.61
°
=
=
kPa
300
@
sat
1
T
T
and
kJ/kg
52
.
54
)
13
.
198
)(
009321
.
0
(
67
.
52
009321
.
0
/kg
m
)
0007736
.
0
067978
.
0
(
/kg
m
)
0007736
.
0
0014
.
0
(
1
1
3
3
1
1
=
+
=
+
=
=
−
−
=
−
=
fg
f
fg
f
h
x
h
h
x
v
v
v
The total enthalpy is then
kJ
545.2
=
=
=
)
kJ/kg
52
.
54
)(
kg
10
(
1
1
mh
H
The final state is also saturated mixture. Repeating the calculations at this state,
C
21.55
°
=
=
kPa
600
@
sat
2
T
T
kJ/kg
64
.
84
)
90
.
180
)(
01733
.
0
(
51
.
81
01733
.
0
/kg
m
)
0008199
.
0
034295
.
0
(
/kg
m
)
0008199
.
0
0014
.
0
(
2
2
3
3
2
2
=
+
=
+
=
=
−
−
=
−
=
fg
f
fg
f
h
x
h
h
x
v
v
v
kJ
846.4
=
=
=
)
kJ/kg
64
.
84
)(
kg
10
(
2
2
mh
H
R134a
300 kPa
10 kg
P
2
1
This preview has intentionally blurred sections. Sign up to view the full version.
View Full Document 363
Heat is supplied to a pistoncylinder device that contains water at a specified state. The
volume of the tank, the final temperature and pressure, and the internal energy change of water are
to be determined.
Properties
The saturated liquid properties of water at 200
°
C are:
v
f
= 0.001157 m
3
/kg and
u
f
=
850.46 kJ/kg (Table A4).
This is the end of the preview. Sign up
to
access the rest of the document.
This homework help was uploaded on 04/16/2008 for the course ME 2322 taught by Professor Oler during the Spring '06 term at Texas Tech.
 Spring '06
 OLER

Click to edit the document details