Ex
10 3
.
.
A tube of 60 mm outer diameter is insulated with a 50 mm layer of silica foam, for which
the conductivity is 0.055 W/(m - °C) followed itt a 40 mm layer of cork with a conductivity
of 0.05 W/(m - °C). If the temperature of the outer surface of the pipe is 150 °C and the
temperature of the outer surface of the cork is 30 °C . Calculate the heat loss in Watts per
meter of pipe.
Given
:
Let
A
be
for
silica
B
be
for
cork
↑
be the
temp
Cork
Silica
the
of the
Tz
temp
the
be
T.
Tz
ka
Ki
outer surface
cork
1502
=
Rea'd
30 %
=
W
0 055
=
=
outer surface
pipe
the
on
the
of
.
0
m
.
M
sol'n
:
↑ solve
&
a
↳
Ti
=It
q
1502
-
30 %
L
in
[0.08
In
t
-
v
Find
We ,
by
30mm
=
=
=
0 03
.
2
=
0
=
0
2
3
" To
r,
60mm
&
2. it
#
↳
r,
.
.
[
=
-
E
q
for
Tz
-
1
i
03m
08m
+
+
0 .
05m
0 04m
.
=
=
⑰
0
0
.
.
08m
12
m
m
T2
⑨
Y
TB
T.
(
.
-
↓
:
=
%L
W
05
.
&
-
-
on
,
Cork
Silica
40mm
-
10 055W
.
= 29 06
w
.
[0 . ]
2 i 10
.
05
=
150 %
=
30 %