Question: The exhaust gases of an automotive engine leave the combustion chamber and enter a 8-ft-long and 3.5-in-diameter thin-walled steel exhaust pipe at 800°F and 15.5 psia at a rate of 0.05 lbm/s. The surrounding ambient air is at a temperature of 80°F, and the heat transfer coefficient on the outer surface of the exhaust pipe is 3 Btu/h?ft2 °F. Assuming the exhaust gases to have the properties of air, determine
(a) the velocity of the exhaust gases at the inlet of the exhaust pipe and
(b) the temperature at which the exhaust gases will leave the pipe and enter the air.