Hot air flows with a mass flow rate m = 0.09 kg/s through an uninsulate of diameter D = 0.15 m, which is in the crawlspace of a house. The hot air enters at 110°C and, after a distance of L 5 m, cools to 80°C. The heat transfer coefficient between the duct surface and the ambient air at To 0°C is known to be h, = 9 W/m²K. (a) Calculate the heat loss from the duct over the length L. (b) Determine the heat flux and the surface temperature at x = L. (c) Determine the heat flux and the surface temperature at x = 0. neet %3D Assume, for air at Tm 368 K: Cp = 1011 J/kg.K; for air at Tm,L = 353 K: k = 0.030 W/m.K, u 209x10 N.s/m2, Pr= 0.70; for air at Tm,0 =383 K: k = 0.033 W/m.K, u 223x10 N.s/m2, Pr = 0.69. Show all calculations.

Hot air flows with a mass flow rate m = 0.09 kg/s through an uninsulate of diameter D = 0.15 m, which is in the crawlspace of a house. The hot air enters at 110°C and, after a distance of L 5 m, cools to 80°C. The heat transfer coefficient between the duct surface and the ambient air at To 0°C is known to be h, = 9 W/m²K. (a) Calculate the heat loss from the duct over the length L. (b) Determine the heat flux and the surface temperature at x = L. (c) Determine the heat flux and the surface temperature at x = 0. neet %3D Assume, for air at Tm 368 K: Cp = 1011 J/kg.K; for air at Tm,L = 353 K: k = 0.030 W/m.K, u 209x10 N.s/m2, Pr= 0.70; for air at Tm,0 =383 K: k = 0.033 W/m.K, u 223x10 N.s/m2, Pr = 0.69. Show all calculations.

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 7.24P

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