Thermodynamics HW Solutions 796

Thermodynamics HW Solutions 796 - Chapter 10 Boiling and...

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Chapter 10 Boiling and Condensation 10-15E Water is boiled at 1 atm pressure and thus at a saturation (or boiling) temperature of T sat = 212 ° F by a horizontal polished copper heating element whose surface temperature is maintained at T s = 988 ° F. The rate of heat transfer to the water per unit length of the heater is to be determined. Assumptions 1 Steady operating conditions exist. 2 Heat losses from the boiler are negligible. Properties The properties of water at the saturation temperature of 212 ° F are and (Table A-9E). The properties of the vapor at the film temperature of are, by interpolation, (Table A-16E) ρ l = 5982 . l b m / f t 3 h fg = 970 Btu / lbm TT T fs =+ = + = ° () / ( ) / sat F 2 212 988 2 600 F ft Btu/h 02640 . 0 F Btu/lbm 4799 . 0 C h Btu/lbm 0.05101 lbm/ft 02395 . 0 3 ° = ° = = = v pv v v k μ P = 1 atm Water, 212 ° F Heating element Also, g = 32.2 ft/s 2 = 32.2 × (3600) 2 ft/h 2 . Note that we expressed the properties in units that will cancel each other in boiling heat transfer relations. Also note that we used vapor properties at 1 atm pressure from
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This note was uploaded on 01/24/2012 for the course PHY 4803 taught by Professor Dr.danielarenas during the Fall '10 term at UNF.

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