Author: admin

Air is flowing at a rate of 10lb/h inside a round tube with
a diameter of 1.5 in. and length of 10 in., similar to Figure 13–32 on page
644. The initial temperature of the air entering the tube is 50F. The wall of
the tube has a uniform constant temperature of 200F. The specific heat of the
air is 0.24 Btu/(lb-F), the convection coefficient between the air and the
inner wall of the tube is 3.0 Btu/h-ft
2
– F), and the thermal
conductivity is 0.017 Btu/h-ft
2
– F). Determine the temperature of
the air along the length of the tube and the heat flow at the inlet and outlet
of the tube.

1. For the one-dimensional flow through the porous media
shown in Figure P14–1, determine the potentials at one-third and two-thirds of
the length. Also determine the velocities in each element. Let A = 0:2 m
2
.
2. For the one-dimensional flow through the porous medium
shown in Figure P14–2 with fluid flux at the right end, determine the
potentials at the third points. Also determine the velocities in each element.
Let A =2 m
2
.

1. For the plane truss shown in Figure P15–4, bar element 1
is subjected to a uniform temperature rise of 30 F. Let E = 30
10
6
psi, A = 2 in
2
, and a = 7:0
10
-6
(in./in.)/ F. The
lengths of the truss elements are shown in the figure. Determine the stresses
in each bar. (Hint: Use Problem 3.21 for (K .)
2. For the structure shown in Figure P15–5, bar element 1 is
subjected to a uniform temperature rise of T = 20 C. Let E = 210 GPa, A ¼=2
10
-2
m
2
, and a = 12
10
-6
(mm/mm)/
C. Determine the stresses in each bar.