Author: admin

1. For the two-dimensional body shown in Figure P13–36,
determine the temperature distribution. The left and right sides are insulated.
The top surface is subjected to heat transfer by convection. The bottom and
internal portion surfaces are maintained at 300 C.
2. Determine the temperature distribution and rate of heat
flow through the plain carbon steel ingot shown in Figure P13–37. Let k = 60W/
m-KÞ for the steel. The top surface is held at 40C, while the underside surface
is held at 0 C. Assume that no heat is lost from the sides.

Determine the temperature distribution and rate of heat flow
per foot length from a 5 cm outer diameter pipe at 180 C placed eccentrically
within a larger cylinder of insulation (k = 0:058W/ m-C) as shown in Figure
P13–38. The diameter of the outside cylinder is 15 cm, and the surface
temperature is 20 C.

1. Determine the temperature distribution and rate of heat
flow in the molded foam insulation (k = 0:17 Btu/h-ft-F) shown in Figure
P13–39.
2. Now add a 6 in. thick concrete floor to the model of
Figure P13–40 (as shown in Figure P13–41). Determine the temperature
distribution and the heat transfer through the concrete and soil. Use the same
properties as shown in Problem 13–40.

For the basement wall shown in Figure P13–40, determine the
temperature distribution and the heat transfer through the wall and soil. The
wall is constructed of concrete (k = 1:0 Btu/h-ft-F). The soil has an average
thermal conductivity of k = 0:85 Btu/h-ft-F. The inside air is maintained at 70
F with a convection coefficient h = 2:0 Btu/h-ft
2
– F. The outside
air temperature is 10 F with a heat transfer coefficient of h = 6 Btu/h-ft
2
–
F. Assume a reasonable distance from the wall of five feet that the horizontal
component of heat transfer becomes negligible. Make sure this assumption is
correct.

Aluminum fins (k = 170W/ m-K) with triangular profiles shown
in Figure P13–42 are used to remove heat from a surface with a temperature of
160 C. The temperature of the surrounding air is 25 C. The natural convection
coefficient is h = 25 W/ m2-K. Determine the temperature distribution
throughout and the heat loss from a typical fin.

The forging hammer shown in Figure P13–43 is subjected to a
surface temperature of 210 C acting on the lower flat surface of the steel
hammer head. The hammer’s thermal conductivity is 20 W/m-K and the room
temperature is assumed to be 40 C with a convection coefficient of 3:216
10
-6
J/(s -C-mm
2
).
Determine the temperature distribution throughout the
hammer.

The Allen wrench shown in Figure P13–44 is unloaded but now
exposed to a temperature of 300 K, at its lower end, while the other end has a
heat flux of 10 W/m2 acting over the end surface. Determine the temperature
distribution throughout the wrench. The thermal conductivity of the material is
43.6 W/m-K. Assume the wrench is insulated around the perimeter. The dimensions
of the wrench are those of Figure P11–18.

The forklift from Figure P13–45 (detailed dimensions shown
in Figure P11–20) has its load removed. The fork is made of AISI 4130 steel.
The thermal conductivity of the steel is 35 W/mC. The top surface of the fork
is at 50 C. The other surfaces of the L-shaped appendages located at the upper
and lower left sides of the forklift are at room temperature (assume 25 C).
Determine the temperature distribution throughout the fork.

The radio control car front steering unit in Figure P13–46
(detailed dimensions shown in Figure P11–21) is now relieved of stress, but its
base has an applied temperature of 100F. The lower surface of the lower
right-side flange has an applied temperature of 50F. Other surfaces are exposed
to Ty = 70F and h = 1 Btu/h-ft
2
– F. The unit is made of ABS
(acrylonitrile butadine stryrene) with k = 0.104 Btu/ft-hr- F. Determine the
temperature throughout the steering unit.

The hitch shown in Figure P13–47 (detailed dimensions shown
in Figure P11–22) is unloaded but has an applied temperature of 200 F to the
front end and an applied temperature of 10 F to the rear surface. Determine the
temperature distribution throughout the hitch. The rest of the surfaces are
exposed to ambient temperature of 70F with h = 2 Btu/h-ft
2
– F.