1. Air is flowing in a pipe which is maintained at a constant surface temperature Ts. The air enters the pipe at a uniform temperature Tmi. Plot on a temperature-distance diagram the pipe surface temperature and the air mean temperature.

(2. Air is flowing in a pipe which is exposed to a constant heat flux qs". The air enters the pipe at a uniform temperature of Tmi.

a) Plot on a temperature-distance diagram the pipe surface temperature and the air mean temperature and explain why the curves are this way.

b) Using the first law of Thermodynamics as we did in class, develop an expression for the air mean flow temperature.

3. How is the Nusselt number of a fully developed flow changing along the position?