Chapter 10 Boiling and Condensation10-56 Saturated steam at a saturation temperature of Tsat= 50°C condenses on the outer surfaces of a tube bank with 20 tubes in each column maintained at 20°C. The average heat transfer coefficient and the rate of condensation of steam on the tubes are to be determined. Assumptions1Steady operating conditions exist.2The tubes are isothermal. PropertiesThe properties of water at the saturation temperature of 50°C are hfg= 2383×103J/kg and ρv= 0.0831 kg/m3. The properties of liquid water at the film temperature of TTTfs=+=()/sat2(50 + 20)/2 = 35°C are (Table A-9), Steam 50°C 20°CCondensate flow 20 tubes in a column ρμνμlllllpllk==×⋅==×=⋅°°−−994 00 720 100724 1041780623336../..kg / mkg / m sm/sC J/kgCW/m C2Analysis(a) The modified latent heat of vaporization is J/kg102468=C0)2C(50J/kg41780.68+J/kg102383)(68.033sat*×°−°⋅××=−+=splfgfgTTChhThe heat transfer coefficient for condensation on a single horizontal tube is CW/m8425m)C(0.015)2050(s)kg/m10720.0()CW/m623.0)(J/kg102468)(
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