Question- In one stage of a process for the manufacture of liquid air, air as a gas at 4 atm absolute and 250 K is passed through a long insulated 3-in. ID pipe, in which the pressure drops 3 psi because of frictional resistance to flow. Near the end of the line, the air is expanded through a valve to 2 atm absolute. State all assumptions.
1. Compute the temperature of the air just downstream of the valve.
2. If the air enters the pipe at the rate of 100 lb/hr, compute the velocity just downstream of the valve.
Please explain why you chose your answer!