Chapter 3 Steady Heat Conduction3-155 Hot water is flowing through a 3-m section of a cast iron pipe. The pipe is exposed to cold air and surfaces in the basement, and it experiences a 3°C-temperature drop. The combined convection and radiation heat transfer coefficient at the outer surface of the pipe is to be determined. Assumptions1Heat transfer is steady since there is no indication of any significant change with time. 2 Heat transfer is one-dimensional since there is thermal symmetry about the centerline and no significant variation in the axial direction. 3 Thermal properties are constant. PropertiesThe thermal conductivity of cast iron is given to be k= 52 W/m⋅°C. Analysis Using water properties at room temperature, the mass flow rate of water and rate of heat transfer from the water are determined to be &&(/&&(.)()mVVAQmCTccp====°−°ρρπ1000410670 67kg / m )(1.5 m / s)
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