An insulated steam pipe is used to transport high-temperature steam from one building to another. Thepipe has a diameter of 500 mm, a surface temperature of 164 °C and is exposed to ambient air at -10 °C.The pipe is subjected to an extermal forced convection as the air moves in a cross-flow over the pipe at aspeed of 5 m/s (see figure below).a. What are the main assumptions?b. What is the heat loss per unit length of pipe without insulation?c. What is the heat loss per unit length of pipe if the insulation thickness is 10 mm?V = 5 m/sToo= -10 °CAirTsi = 150 °CInsulation k, = 0.026 W/m-KD = 500 mmTs.oOs8s 50 mmSteamThermophysical Properties of Air at Atmospheric Pressure'k 104.107(N-s/m)v• 10(m/s)a 10(m/s)T(K)(kg/m')(kJ/kg - K)(W/m K)Pr1003.55621.03271.12.009.342.540.7861502.33641.012103.44.42613.85.840.7582001.74581.007132.57.59018.110.30.7372501.39471.006159.611.4422.315.90.7203001.16141.007184.615.8926.322.50.7073500.99501.009208.220.9230.029.90.7004000.87111.014230.126.4133.838.30.6901.0211.0304500.7740250.732.3937.347.20.6865000.6964270.138.7940.756.70.6845500.63291.040288.445.5743.966.70.683For gases at atmospheric pressure, the ideal gas model applies, and p- p/RT.Convection Heat Transfer Correlations for External FlowFlowCorrelationRange of Applicability0.62 Re2 Pr31/45/8 4/5hD0.3 +kRep282,000Cylinder Nup =.Rep Pr 0.2

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An insulated steam pipe is used to transport high-temperature steam from one building to another. The pipe has a diameter of 500 mm, a surface temperature of 164 °C and is exposed to ambient air at -10 °C. The pipe is subjected to an external forced convection as the air moves in a cross-flow over the pipe at a speed of 5 m/s (see figure below). a. What are the main assumptions? b. What is the heat loss per unit length of pipe without insulation? c. What is the heat loss per unit length of pipe if the insulation thickness is 10 mm? V = 5 m/s Too=-10 °C Air Tsi= 150 °C !! Insulation k, = 0.026 W/m-K -T20 D= 500 mm- Osôs 50 mm Steam

An insulated steam pipe is used to transport high-temperature steam from one building to another. The pipe has a diameter of 500 mm, a surface temperature of 164 °C and is exposed to ambient air at -10 °C. The pipe is subjected to an external forced convection as the air moves in a cross-flow over the pipe at a speed of 5 m/s (see figure below). a. What are the main assumptions? b. What is the heat loss per unit length of pipe without insulation? c. What is the heat loss per unit length of pipe if the insulation thickness is 10 mm? V = 5 m/s Too=-10 °C Air Tsi= 150 °C !! Insulation k, = 0.026 W/m-K -T20 D= 500 mm- Osôs 50 mm Steam

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 7.41P

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