You are designing a piping system to facilitate the transfer of water from one industrial process to the next. You need the water to condense from saturated vapor to saturated liquid at a constant 1000 kPa as it flows through the piping system. The pipe is to be made of plain carbon steel with thermal conductivity ? = 60 W m-K⁄ and inner and outer radii ?? = 5 cm and ?? = 7 cm, respectively. The thermodynamic property table at the end of this problem will be helpful throughout your analysis. a) If the convection coefficient between the steam and inner wall of the pipe is “very large”, what is the temperature of the inner pipe wall along its entire length? (Hint: Isobaric phase change is also iso___?) b) The fluid surrounding the pipe has temperature ?∞ = 30°C and the convection coefficient from the pipe to this fluid is ℎ = 100 W/m2⋅K. What is the heat transfer rate out of the pipe, per unit meter of pipe? You may neglect radiation effects. Use a thermal resistance network in your analysis. c) The mass flow rate through the piping system is to be 0.75 kg/s. How long must the pipe be to meet this design criteria?

You are designing a piping system to facilitate the transfer of water from one industrial
process to the next. You need the water to condense from saturated vapor to saturated
liquid at a constant 1000 kPa as it flows through the piping system. The pipe is to be made
of plain carbon steel with thermal conductivity ? = 60 W m-K⁄ and inner and outer radii
?? = 5 cm and ?? = 7 cm, respectively. The thermodynamic property table at the end of this
problem will be helpful throughout your analysis.
a) If the convection coefficient between the steam and inner wall of the pipe is “very
large”, what is the temperature of the inner pipe wall along its entire length?
(Hint: Isobaric phase change is also iso___?)
b) The fluid surrounding the pipe has temperature ?∞ = 30°C and the convection
coefficient from the pipe to this fluid is ℎ = 100 W/m2⋅K. What is the heat transfer
rate out of the pipe, per unit meter of pipe? You may neglect radiation effects. Use
a thermal resistance network in your analysis.
c) The mass flow rate through the piping system is to be 0.75 kg/s. How long must the
pipe be to meet this design criteria?