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Unformatted text preview: densation heat transfer?
10–42 The Reynolds number for condensate flow is defined
·
as Re 4m /p l, where p is the wetted perimeter. Obtain simplified relations for the Reynolds number by expressing p and
·
m by their equivalence for the following geometries: (a) a vertical plate of height L and width w, (b) a tilted plate of height L
and width w inclined at an angle from the vertical, (c) a vertical cylinder of length L and diameter D, (d) a horizontal
cylinder of length L and diameter D, and (e) a sphere of diameter D.
10–43 Consider film condensation on the outer surfaces of N
horizontal tubes arranged in a vertical tier. For what value of N 4 cm
Steam
30°C
Condensate L=2m 20°C FIGURE P10–46
10–47E Saturated steam at 95°F is condensed on the outer
surfaces of an array of horizontal pipes through which cooling
water circulates. The outer diameter of the pipes is 1 in. and the
outer surfaces of the pipes are maintained at 85°F. Determine
(a) the rate of heat transfer to the cooling water circulating in
the pipes and (b) the rate of condensation of steam per unit
length of a single horizontal pipe. cen58933_ch10.qxd 9/4/2002 12:38 PM Page 557 557
CHAPTER 10 10–48E Repeat Problem 10–47E for the case of 32 horizontal pipes arranged in a rectangular array of 4 pipes high and
8 pipes wide.
10–49 Saturated steam at 55°C is to be condensed at a rate of
10 kg/h on the outside of a 3cmouterdiameter vertical tube
whose surface is maintained at 45°C by the cooling water. Determine the tube length required.
10–50 Repeat Problem 10–49 for a horizontal tube. Answer: 0.70 m 10–51 Saturated steam at 100°C condenses on a 2m 2m
plate that is tilted 40° from the vertical. The plate is maintained
at 80°C by cooling it from the other side. Determine (a) the average heat transfer coefficient over the entire plate and (b) the
rate at which the condensate drips off the plate at the bottom.
10–52 Reconsider Problem 10–51. Using EES (or
other) software, investigate t...
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 Spring '10
 Ghaz

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