a. Air flows adiabatically through a long straight horizontal duct, 0.25 m diameter, at a measured mass flow rate of 40 kg/s. At a particular section along the duct the measured values of static temperature T 5 150C and static pressure p 5 550 kPa. Determine the average velocity of the airflow and its stagnation temperature.
b. At another station further along the duct, measurements reveal that the static temperature has dropped to 147°C as a consequence of wall friction. Determine the average velocity and the static pressure of the airflow at this station. Also determine the change in entropy per unit of mass flow between the two stations.
For air assume that R 5 287 J/(kg K) and γ 5 1:4.