PROBLEM 4.20
KNOWN:
Dimensions, thermal conductivity and inner surface temperature of furnace wall.
Ambient
conditions.
FIND:
Heat loss.
SCHEMATIC:
ASSUMPTIONS:
(1) Steadystate, (2) Uniform convection coefficient over entire outer surface of
container, (3) Negligible radiation losses.
A
NALYSIS:
From the thermal circuit, the heat loss is
s,i
cond(2D)
conv
TT
q
RR
∞
−
=
+
where R
conv
= 1/hA
s,o
= 1/6(hW
2
) = 1/6[5 W/m
2
⋅
K(5 m)
2
] = 0.00133 K/W.
From Equation (4.21), the two
imensional conduction resistance is
d
cond(2D)
1
R
Sk
=
where the shape factor S must include the effects of conduction through the 8 corners, 12 edges and 6
This is the end of the preview. Sign up
to
access the rest of the document.
This note was uploaded on 12/07/2010 for the course MAE Heat Trans taught by Professor Lee,j.s. during the Spring '10 term at Seoul National.
 Spring '10
 LEE,J.S.
 Heat Transfer

Click to edit the document details