Question

1. Recall from homework set #2, air in a closed system undergoes two processes in series. First the air is compressed from state 1 to state 2 in a polytropic manner with n=1.3. Next the air is expanded at constant pressure from state 2 back to state 3, which is at the original volume. The following state point properties are known: P1=110 kPa, v1=0.8m3/kg, v2=0.4 m3/kg. Using state point information from homework set #2, determine the following.a. Draw the processes and label the state points on a single T-‐‐s diagram.b. Determine the entropy produced per mass from state 1 to state 2. Use a
b

Answer 1

@osprey

Answer 2

I think I know how to do this problem. Can I assume air is an ideal gas?

Answer 3

1. Recall from homework set #2, air in a closed system undergoes two processes in series. First the air is compressed from state 1 to state 2 in a polytropic manner with n=1.3. Next the air is expanded at constant pressure from state 2 back to state 3, which is at the original volume. The following state point properties are known: P1=110 kPa, v1=0.8m3/kg, v2=0.4 m3/kg. Using state point information from homework set #2, determine the following.a. Draw the processes and label the state points on a single T-‐‐s diagram.b. Determine the entropy produced per mass from state 1 to state 2. Use a
boundary temperature of 340 K.c. Determine the entropy produced per mass from state 2 to state 3. Use a boundary temperature of 550 K.

Answer 4

@IrishBoy123

Answer 5

@raffle_snaffle I'd tend to assume that air was an ideal gas unless anything suggested otherwise. pV=nRT rules OK ! so to speak.