Superheated steam pressure at a 1 atm, mean temperature of 800K, and mass flow rate of 0.15kg/s enters a thin walled,metalic pipe of diameter D=0.2m. The outside of the pipe is exposed to a cross flow of air at ambient Temprature= 300 K and V=10m/s,which cools the steam to 400 K at the pipe outlet.Use the follwing properities for the air: v=3.8x10^-5 m^2/s,k=0.039W/m-K.Pr=0.684 Refer to table A.4 for steam(water vapor).
a) determine the external flow convection coefficient(ho)
b) determine the internal flow convection coefficient(hi),assuming fully develped flow
c) determine the length of the pipe(L).