Air (assumed to be an ideal gas) is contained in a piston-cylinder assembly at an initial state of 1 bar with a volume of 1 m3. The mass of air contained in the cylinder is 1 kg. During any expansion or compression of the air, the pressure remains constant. Heat transfer to the air in the cylinder is used to cause an expansion of the air until the final volume is twice the original volume.
a. determine the initial temperature of the air in the cylinder.
b. determine the final temperature of the air.
c. determine the required heat transfer (kj) (u’s found via b.11).
d. another engineer proposes to replace the heat transfer with a revolving impellor. That is a motor external to the cylinder is attached to a shaft passing through the end of the cylinder which revolves a set of impellor blades. The idea is to use work transfer (by agitating the air with the rotating impellor). This process will be adiabatic. The air undergoes exactly the same change. What is the work transfer required?