The average temperature of the soil to a considerable depth is approximately 277.6 K (40°F) during a winter day. If the outside air temperature suddenly drops to 255.4 K (0°F) and stays there, how long will it take for a pipe 3.05 m (10 ft) below the surface to reach 273.2 K (32°F)? The convective coefficient is h = 8.52 W/m2 -K (1.5 BTU/h-ft2 -°F). The soil physical properties can be taken as 5.16 x 10–7 m/s (0.02 ft2 /h) for the thermal diffusivity and 1.384 W/m-K (0.8 BTU/h-ft-°F) for the thermal conductivity

The average temperature of the soil to a considerable depth is approximately 277.6 K (40°F) during a winter day. If the outside air temperature suddenly drops to 255.4 K (0°F) and stays there, how long will it take for a pipe 3.05 m (10 ft) below the surface to reach 273.2 K (32°F)? The convective coefficient is h = 8.52 W/m2 -K (1.5 BTU/h-ft2 -°F). The soil physical properties can be taken as 5.16 x 10–7 m/s (0.02 ft2 /h) for the thermal diffusivity and 1.384 W/m-K (0.8 BTU/h-ft-°F) for the thermal conductivity

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.

Chapter6: Forced Convection Over Exterior Surfaces

Section: Chapter Questions

Problem 6.4P: An electrical transmission line of 1.2-cm diameter carries a current of 200 amps and has a...

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