Steam in a heating system flows through tubes whose outer diameter is 5 cm and whose walls are maintained at a temperature of 180 C. Circular aluminum alloy 2024-T6 fins (k =186W/m °C) of outer diameter 6 cm and constant thickness 1 mm are attached to the tube. The space between the fins is 3 mm, and thus there are 250 fins per meter length of the tube. Heat is transferred to the surrounding air at T = 25°C, with a heat transfer coefficient of 40 W/m2.°C. %3D Determine the increase in heat transfer from the tube per meter of its length as a result of adding fins. 25 em 3 cm

Steam in a heating system flows through tubes whose outer diameter is 5 cm and whose walls are maintained at a temperature of 180 C. Circular aluminum alloy 2024-T6 fins (k =186W/m °C) of outer diameter 6 cm and constant thickness 1 mm are attached to the tube. The space between the fins is 3 mm, and thus there are 250 fins per meter length of the tube. Heat is transferred to the surrounding air at T = 25°C, with a heat transfer coefficient of 40 W/m2.°C. %3D Determine the increase in heat transfer from the tube per meter of its length as a result of adding fins. 25 em 3 cm

Principles of Heat Transfer (Activate Learning with these NEW titles from Engineering!)

8th Edition

ISBN:9781305387102

Author:Kreith, Frank; Manglik, Raj M.

Publisher:Kreith, Frank; Manglik, Raj M.

Chapter7: Forced Convection Inside Tubes And Ducts

Section: Chapter Questions

Problem 7.4P

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Determine the rate of heat transfer per meter length to a light oil flowing through a 2.5-cm-ID, 60-cm-long copper tube at a velocity of 0.03 m/s. The oil enters the tube at 16C, and the tube is heated by steam condensing on its outer surface at atmospheric pressure with a heat transfer coefficient of 11.3 kW/m K. The properties of the oil at various temperatures are listed in the following table: Temperature, T(C) 15 30 40 65 100 (kg/m3) 912 912 896 880 864 c(kJ/kgK) 1.80 1.84 1.925 2.0 2.135 k(W/mK) 0.133 0.133 0.131 0.129 0.128 (kg/ms) 0.089 0.0414 0.023 0.00786 0.0033 Pr 1204 573 338 122 55
Steam passes into tubes in a heating system whose outer diameter is 3 cm and whose wall is held at a temperature of 120°C. Tubes are connected to circular aluminium alloy fins (k = 180 W/m. ° C) with an outer diameter of 6 cm and a constant thickness of 2 mm. The distance between the two fins is 3 mm and the tube length is 200 fins per meter. With h = 60 W/m2.°C, the heat is transmitted to the ambient air at 25°C. Evaluate the increase in heat transfer from the tube per meter of its length as a result of adding fins.
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