Your friend left your house and is now driving 40 miles per hour, but she has been speeding up the whole time since she left your house, and has gone 10 miles. How long has she been driving?
A) shorter than 15 minutes B) longer than 15 minutes C) 15 minutes
B
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In a shell of a shell and tube heat exchanger with two shell passes and eight tube passes, 12.6 kg/s of water is heated in the shell from 800C to 150°C. Hot exhaust gases having roughly the same physical properties as air enter the tubes at 340°C and leave at 180°C. The total surface, based on the outer tube surface, is 930 m2 . Determine (a) the log-mean temperature difference if the heat exchanger were simple counterflow type, (b) the correction factor F for the actual arrangement, (c) the effectiveness of the heat exchanger, (d) the average overall heat transfer coefficient.
GIVEN
• A tubular heat exchanger with 2 shell passes and 8 tube passes
• Water in the shell, exhaust gases in the tubes
• Exhaust gases have roughly the same physical properties as air
• Water flow rate m w= 12.6 kg/s
• Water temperatures
? Tw,in = 80°C
? Tw,out = 150°C
• Exhaust temperatures
? Te,in = 340°C
? Te,out = 180°C
• Surface are (A) = 930 m2
FIND
(a) LMTD if the exchanger is a simple counterflow type
(b) Correction F for the actual arrangement
(c) Effectiveness (e)
(d) The overall heat transfer coefficient (U)
SKETCH
PROPERTIES AND CONSTANTS
the specific heat of water at the mean temperature of 130°C (cpw) = 4244.5 W/(kg K)
If the distance between us and a star is doubled, its apparent brightness will decrease by a factor of four
Indicate whether the statement is true or false
An area of 1.00 × 102 cm2 is how many square meters?
A) 1.00 m2 B) 1.00 × 102 m2 C) 1.00 × 10-2 m2 D) 1.00 × 104 m2 E) 1.00 × 10-3 m2
The index of refraction for a certain material is 1.399 for red light and 1.432 for blue light. Light containing both of these colors is traveling in vacuum and strikes a flat sheet of this material
Find the angle separating the two colors in the refracted light in the sheet if the angle of incidence is 60.00°.