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Unformatted text preview: lished steel pan placed on top of a heating unit.
The inner surface of the bottom of the pan is maintained at
110°C. If the diameter of the bottom of the pan is 25 cm, determine (a) the rate of heat transfer to the water and (b) the rate of
evaporation. 1 atm 3 kW 1 atm FIGURE P10–16
110°C 10–17 Repeat Problem 10–16 for a location at an elevation of
1500 m where the atmospheric pressure is 84.5 kPa and thus
the boiling temperature of water is 95°C.
Answers: 100.9°C, 10.3°C 10–18 Water is boiled at sea level in a coffee maker equipped
with a 20-cm long 0.4-cm-diameter immersion-type electric
1 atm FIGURE P10–11
10–12 Water is to be boiled at atmospheric pressure on a
3-cm-diameter mechanically polished steel heater. Determine
the maximum heat flux that can be attained in the nucleate
boiling regime and the surface temperature of the heater surface in that case.
Reconsider Problem 10–12. Using EES (or
other) software, investigate the effect of local
atmospheric pressure on the maximum heat flux and the temperature difference Ts Tsat. Let the atmospheric pressure vary Coffee
1L 10–13 FIGURE P10–18 cen58933_ch10.qxd 9/4/2002 12:38 PM Page 555 555
CHAPTER 10 heating element made of mechanically polished stainless steel.
The coffee maker initially contains 1 L of water at 18°C. Once
boiling starts, it is observed that half of the water in the coffee
maker evaporates in 25 min. Determine the power rating of the
electric heating element immersed in water and the surface
temperature of the heating element. Also determine how long it
will take for this heater to raise the temperature of 1 L of cold
water from 18°C to the boiling temperature.
Boiler 150°C Repeat Problem 10–18 for a copper heating element. 10–20 A 65-cm-long, 2-cm-diameter brass heating element is
to be used to boil water at 120°C. If the surface temperature of
the heating element is not to exceed 125°C, determine the
highest rate of steam production in the boiler,...
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This note was uploaded on 01/28/2010 for the course HEAT ENG taught by Professor Ghaz during the Spring '10 term at University of Guelph.
- Spring '10