Thermodynamics HW Solutions 850

# Thermodynamics HW Solutions 850 - Chapter 10 Boiling and...

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Chapter 10 Boiling and Condensation 10-73 Saturated ammonia at a saturation temperature of T sat = 25 ° C condenses on the outer surface of vertical tube which is maintained at 15 ° C by circulating cooling water. The rate of heat transfer to the coolant and the rate of condensation of ammonia are to be determined. Assumptions 1 Steady operating conditions exist. 2 The tube is isothermal. 3 The tube can be treated as a vertical plate. 4 The condensate flow is turbulentr over the entire tube (this assumption will be verified). 5 The density of vapor is much smaller than the density of liquid, ρ vl << . Properties The properties of ammonia at the saturation temperature of 25 ° C are h fg = 1166 × 10 3 J/kg and ρ v = 7.809 kg/m 3 . The properties of liquid ammonia at the film temperature of TT T fs =+ = () / sat 2 (25 + 15)/2 = 20 ° C are (Table A-11), Ammonia 25 ° C Condensate L tube = 2 m D =3.2 cm 15 ° C 463 . 1 Pr C W/m 4927 . 0 C J/kg 4745 C /s m 10 2489 . 0 / s kg/m 10 519 . 1 kg/m 2 . 610 2 6 4 - 3 = ° = ° = × = = × = = l l pl l l l l l k ρμ ν μ Analysis ( a
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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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